diff --git a/packages/beacon-node/src/chain/errors/blobSidecarError.ts b/packages/beacon-node/src/chain/errors/blobSidecarError.ts
index 410574594911..71118d8b8f9d 100644
--- a/packages/beacon-node/src/chain/errors/blobSidecarError.ts
+++ b/packages/beacon-node/src/chain/errors/blobSidecarError.ts
@@ -26,7 +26,7 @@ export enum BlobSidecarErrorCode {
 }
 
 export type BlobSidecarErrorType =
-  | {code: BlobSidecarErrorCode.INVALID_INDEX; blobIdx: number; gossipIndex: number}
+  | {code: BlobSidecarErrorCode.INVALID_INDEX; blobIdx: number; subnet: number}
   | {code: BlobSidecarErrorCode.INVALID_KZG; blobIdx: number}
   | {code: BlobSidecarErrorCode.INVALID_KZG_TXS}
   | {code: BlobSidecarErrorCode.INCORRECT_SLOT; blockSlot: Slot; blobSlot: Slot; blobIdx: number}
diff --git a/packages/beacon-node/src/chain/validation/blobSidecar.ts b/packages/beacon-node/src/chain/validation/blobSidecar.ts
index 3b90972f62b1..e2f4ed267d01 100644
--- a/packages/beacon-node/src/chain/validation/blobSidecar.ts
+++ b/packages/beacon-node/src/chain/validation/blobSidecar.ts
@@ -1,6 +1,7 @@
+import {ChainConfig} from "@lodestar/config";
 import {KZG_COMMITMENT_INCLUSION_PROOF_DEPTH, KZG_COMMITMENT_SUBTREE_INDEX0} from "@lodestar/params";
 import {computeStartSlotAtEpoch, getBlockHeaderProposerSignatureSet} from "@lodestar/state-transition";
-import {Root, Slot, deneb, ssz} from "@lodestar/types";
+import {BlobIndex, Root, Slot, deneb, ssz} from "@lodestar/types";
 import {toRootHex, verifyMerkleBranch} from "@lodestar/utils";
 
 import {byteArrayEquals} from "../../util/bytes.js";
@@ -13,16 +14,16 @@ import {RegenCaller} from "../regen/index.js";
 export async function validateGossipBlobSidecar(
   chain: IBeaconChain,
   blobSidecar: deneb.BlobSidecar,
-  gossipIndex: number
+  subnet: number
 ): Promise<void> {
   const blobSlot = blobSidecar.signedBlockHeader.message.slot;
 
-  // [REJECT] The sidecar is for the correct topic -- i.e. sidecar.index matches the topic {index}.
-  if (blobSidecar.index !== gossipIndex) {
+  // [REJECT] The sidecar is for the correct subnet -- i.e. `compute_subnet_for_blob_sidecar(sidecar.index) == subnet_id`.
+  if (computeSubnetForBlobSidecar(blobSidecar.index, chain.config) !== subnet) {
     throw new BlobSidecarGossipError(GossipAction.REJECT, {
       code: BlobSidecarErrorCode.INVALID_INDEX,
       blobIdx: blobSidecar.index,
-      gossipIndex,
+      subnet,
     });
   }
 
@@ -225,3 +226,7 @@ function validateInclusionProof(blobSidecar: deneb.BlobSidecar): boolean {
     blobSidecar.signedBlockHeader.message.bodyRoot
   );
 }
+
+function computeSubnetForBlobSidecar(blobIndex: BlobIndex, config: ChainConfig): number {
+  return blobIndex % config.BLOB_SIDECAR_SUBNET_COUNT;
+}
diff --git a/packages/beacon-node/src/network/gossip/interface.ts b/packages/beacon-node/src/network/gossip/interface.ts
index 9939ed5af657..be7293524ce9 100644
--- a/packages/beacon-node/src/network/gossip/interface.ts
+++ b/packages/beacon-node/src/network/gossip/interface.ts
@@ -54,7 +54,7 @@ export interface IGossipTopic {
 
 export type GossipTopicTypeMap = {
   [GossipType.beacon_block]: {type: GossipType.beacon_block};
-  [GossipType.blob_sidecar]: {type: GossipType.blob_sidecar; index: number};
+  [GossipType.blob_sidecar]: {type: GossipType.blob_sidecar; subnet: number};
   [GossipType.beacon_aggregate_and_proof]: {type: GossipType.beacon_aggregate_and_proof};
   [GossipType.beacon_attestation]: {type: GossipType.beacon_attestation; subnet: number};
   [GossipType.voluntary_exit]: {type: GossipType.voluntary_exit};
diff --git a/packages/beacon-node/src/network/gossip/topic.ts b/packages/beacon-node/src/network/gossip/topic.ts
index 1c34440df2b8..88ef4143f8ff 100644
--- a/packages/beacon-node/src/network/gossip/topic.ts
+++ b/packages/beacon-node/src/network/gossip/topic.ts
@@ -73,7 +73,7 @@ function stringifyGossipTopicType(topic: GossipTopic): string {
     case GossipType.sync_committee:
       return `${topic.type}_${topic.subnet}`;
     case GossipType.blob_sidecar:
-      return `${topic.type}_${topic.index}`;
+      return `${topic.type}_${topic.subnet}`;
   }
 }
 
@@ -181,10 +181,10 @@ export function parseGossipTopic(forkDigestContext: ForkDigestContext, topicStr:
     }
 
     if (gossipTypeStr.startsWith(GossipType.blob_sidecar)) {
-      const indexStr = gossipTypeStr.slice(GossipType.blob_sidecar.length + 1); // +1 for '_' concatenating the topic name and the index
-      const index = parseInt(indexStr, 10);
-      if (Number.isNaN(index)) throw Error(`index ${indexStr} is not a number`);
-      return {type: GossipType.blob_sidecar, index, fork, encoding};
+      const subnetStr = gossipTypeStr.slice(GossipType.blob_sidecar.length + 1); // +1 for '_' concatenating the topic name and the subnet
+      const subnet = parseInt(subnetStr, 10);
+      if (Number.isNaN(subnet)) throw Error(`subnet ${subnetStr} is not a number`);
+      return {type: GossipType.blob_sidecar, subnet, fork, encoding};
     }
 
     throw Error(`Unknown gossip type ${gossipTypeStr}`);
@@ -211,10 +211,10 @@ export function getCoreTopicsAtFork(
     {type: GossipType.attester_slashing},
   ];
 
-  // After Deneb also track blob_sidecar_{index}
+  // After Deneb also track blob_sidecar_{subnet_id}
   if (ForkSeq[fork] >= ForkSeq.deneb) {
-    for (let index = 0; index < config.MAX_BLOBS_PER_BLOCK; index++) {
-      topics.push({type: GossipType.blob_sidecar, index});
+    for (let subnet = 0; subnet < config.BLOB_SIDECAR_SUBNET_COUNT; subnet++) {
+      topics.push({type: GossipType.blob_sidecar, subnet});
     }
   }
 
diff --git a/packages/beacon-node/src/network/network.ts b/packages/beacon-node/src/network/network.ts
index 870fbf303ff4..d8370fc22b5f 100644
--- a/packages/beacon-node/src/network/network.ts
+++ b/packages/beacon-node/src/network/network.ts
@@ -312,9 +312,9 @@ export class Network implements INetwork {
   async publishBlobSidecar(blobSidecar: deneb.BlobSidecar): Promise<number> {
     const slot = blobSidecar.signedBlockHeader.message.slot;
     const fork = this.config.getForkName(slot);
-    const index = blobSidecar.index;
+    const subnet = blobSidecar.index;
 
-    return this.publishGossip<GossipType.blob_sidecar>({type: GossipType.blob_sidecar, fork, index}, blobSidecar, {
+    return this.publishGossip<GossipType.blob_sidecar>({type: GossipType.blob_sidecar, fork, subnet}, blobSidecar, {
       ignoreDuplicatePublishError: true,
     });
   }
diff --git a/packages/beacon-node/src/network/processor/gossipHandlers.ts b/packages/beacon-node/src/network/processor/gossipHandlers.ts
index 029e7ae4db42..3fb7b06e700a 100644
--- a/packages/beacon-node/src/network/processor/gossipHandlers.ts
+++ b/packages/beacon-node/src/network/processor/gossipHandlers.ts
@@ -179,7 +179,7 @@ function getSequentialHandlers(modules: ValidatorFnsModules, options: GossipHand
   async function validateBeaconBlob(
     blobSidecar: deneb.BlobSidecar,
     blobBytes: Uint8Array,
-    gossipIndex: number,
+    subnet: number,
     peerIdStr: string,
     seenTimestampSec: number
   ): Promise<BlockInput | NullBlockInput> {
@@ -202,7 +202,7 @@ function getSequentialHandlers(modules: ValidatorFnsModules, options: GossipHand
     );
 
     try {
-      await validateGossipBlobSidecar(chain, blobSidecar, gossipIndex);
+      await validateGossipBlobSidecar(chain, blobSidecar, subnet);
       const recvToValidation = Date.now() / 1000 - seenTimestampSec;
       const validationTime = recvToValidation - recvToValLatency;
 
@@ -212,10 +212,10 @@ function getSequentialHandlers(modules: ValidatorFnsModules, options: GossipHand
       logger.debug("Received gossip blob", {
         slot: slot,
         root: blockHex,
-        curentSlot: chain.clock.currentSlot,
+        currentSlot: chain.clock.currentSlot,
         peerId: peerIdStr,
         delaySec,
-        gossipIndex,
+        subnet,
         ...blockInputMeta,
         recvToValLatency,
         recvToValidation,
@@ -363,7 +363,7 @@ function getSequentialHandlers(modules: ValidatorFnsModules, options: GossipHand
       const blockInput = await validateBeaconBlob(
         blobSidecar,
         serializedData,
-        topic.index,
+        topic.subnet,
         peerIdStr,
         seenTimestampSec
       );
diff --git a/packages/beacon-node/test/e2e/api/impl/config.test.ts b/packages/beacon-node/test/e2e/api/impl/config.test.ts
index 474826050a3a..078e210cb0cc 100644
--- a/packages/beacon-node/test/e2e/api/impl/config.test.ts
+++ b/packages/beacon-node/test/e2e/api/impl/config.test.ts
@@ -10,8 +10,6 @@ const CONSTANT_NAMES_SKIP_LIST = new Set([
   // This constant can also be derived from existing constants so it's not critical.
   // PARTICIPATION_FLAG_WEIGHTS = [TIMELY_SOURCE_WEIGHT, TIMELY_TARGET_WEIGHT, TIMELY_HEAD_WEIGHT]
   "PARTICIPATION_FLAG_WEIGHTS",
-  // TODO DENEB: Configure the blob subnets in a followup PR
-  "BLOB_SIDECAR_SUBNET_COUNT",
 ]);
 
 describe("api / impl / config", () => {
diff --git a/packages/beacon-node/test/unit/network/gossip/topic.test.ts b/packages/beacon-node/test/unit/network/gossip/topic.test.ts
index f68c2d737fd6..4b323865061e 100644
--- a/packages/beacon-node/test/unit/network/gossip/topic.test.ts
+++ b/packages/beacon-node/test/unit/network/gossip/topic.test.ts
@@ -17,7 +17,7 @@ describe("network / gossip / topic", () => {
     ],
     [GossipType.blob_sidecar]: [
       {
-        topic: {type: GossipType.blob_sidecar, index: 1, fork: ForkName.deneb, encoding},
+        topic: {type: GossipType.blob_sidecar, subnet: 1, fork: ForkName.deneb, encoding},
         topicStr: "/eth2/46acb19a/blob_sidecar_1/ssz_snappy",
       },
     ],
diff --git a/packages/config/src/chainConfig/configs/mainnet.ts b/packages/config/src/chainConfig/configs/mainnet.ts
index ae9a2ec74d1f..a4adc04a1756 100644
--- a/packages/config/src/chainConfig/configs/mainnet.ts
+++ b/packages/config/src/chainConfig/configs/mainnet.ts
@@ -101,6 +101,7 @@ export const chainConfig: ChainConfig = {
   // Deneb
   // `2**12` (= 4096 epochs, ~18 days)
   MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS: 4096,
+  BLOB_SIDECAR_SUBNET_COUNT: 6,
   MAX_BLOBS_PER_BLOCK: 6,
   // MAX_REQUEST_BLOCKS_DENEB * MAX_BLOBS_PER_BLOCK
   MAX_REQUEST_BLOB_SIDECARS: 768,
diff --git a/packages/config/src/chainConfig/configs/minimal.ts b/packages/config/src/chainConfig/configs/minimal.ts
index 6f536bc7732c..d16b03e82c28 100644
--- a/packages/config/src/chainConfig/configs/minimal.ts
+++ b/packages/config/src/chainConfig/configs/minimal.ts
@@ -98,6 +98,7 @@ export const chainConfig: ChainConfig = {
   // Deneb
   // `2**12` (= 4096 epochs, ~18 days)
   MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS: 4096,
+  BLOB_SIDECAR_SUBNET_COUNT: 6,
   MAX_BLOBS_PER_BLOCK: 6,
   // MAX_REQUEST_BLOCKS_DENEB * MAX_BLOBS_PER_BLOCK
   MAX_REQUEST_BLOB_SIDECARS: 768,
diff --git a/packages/config/src/chainConfig/types.ts b/packages/config/src/chainConfig/types.ts
index 513324bdbcb8..291dcc8601a7 100644
--- a/packages/config/src/chainConfig/types.ts
+++ b/packages/config/src/chainConfig/types.ts
@@ -72,6 +72,7 @@ export type ChainConfig = {
 
   // Networking
   MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS: number;
+  BLOB_SIDECAR_SUBNET_COUNT: number;
   MAX_BLOBS_PER_BLOCK: number;
   MAX_REQUEST_BLOB_SIDECARS: number;
 };
@@ -138,6 +139,7 @@ export const chainConfigTypes: SpecTypes<ChainConfig> = {
 
   // Networking
   MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS: "number",
+  BLOB_SIDECAR_SUBNET_COUNT: "number",
   MAX_BLOBS_PER_BLOCK: "number",
   MAX_REQUEST_BLOB_SIDECARS: "number",
 };
diff --git a/packages/validator/src/util/params.ts b/packages/validator/src/util/params.ts
index e8fd1a1e6dc4..825f60e8c7fa 100644
--- a/packages/validator/src/util/params.ts
+++ b/packages/validator/src/util/params.ts
@@ -136,6 +136,7 @@ function getSpecCriticalParams(localConfig: ChainConfig): Record<keyof ConfigWit
 
     // Networking (non-critical as those do not affect consensus)
     MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS: false,
+    BLOB_SIDECAR_SUBNET_COUNT: false,
     MAX_REQUEST_BLOB_SIDECARS: false,
 
     // # Phase0Preset