diff --git a/beacon_node/beacon_chain/src/beacon_chain.rs b/beacon_node/beacon_chain/src/beacon_chain.rs
index 7b1d7a696e4..85af7ef4fc8 100644
--- a/beacon_node/beacon_chain/src/beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/beacon_chain.rs
@@ -61,6 +61,7 @@ use safe_arith::SafeArith;
 use slasher::Slasher;
 use slog::{crit, debug, error, info, trace, warn, Logger};
 use slot_clock::SlotClock;
+use ssz::Encode;
 use state_processing::{
     common::get_indexed_attestation,
     per_block_processing,
@@ -3004,6 +3005,19 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             Signature::empty(),
         );
 
+        let block_size = block.ssz_bytes_len();
+        debug!(
+            self.log,
+            "Produced block on state";
+            "block_size" => block_size,
+        );
+
+        metrics::observe(&metrics::BLOCK_SIZE, block_size as f64);
+
+        if block_size > self.config.max_network_size {
+            return Err(BlockProductionError::BlockTooLarge(block_size));
+        }
+
         let process_timer = metrics::start_timer(&metrics::BLOCK_PRODUCTION_PROCESS_TIMES);
         per_block_processing(
             &mut state,
diff --git a/beacon_node/beacon_chain/src/chain_config.rs b/beacon_node/beacon_chain/src/chain_config.rs
index 9fe09c9822a..4aee06d468c 100644
--- a/beacon_node/beacon_chain/src/chain_config.rs
+++ b/beacon_node/beacon_chain/src/chain_config.rs
@@ -16,6 +16,8 @@ pub struct ChainConfig {
     pub reconstruct_historic_states: bool,
     /// Whether timeouts on `TimeoutRwLock`s are enabled or not.
     pub enable_lock_timeouts: bool,
+    /// The max size of a message that can be sent over the network.
+    pub max_network_size: usize,
 }
 
 impl Default for ChainConfig {
@@ -25,6 +27,7 @@ impl Default for ChainConfig {
             weak_subjectivity_checkpoint: None,
             reconstruct_historic_states: false,
             enable_lock_timeouts: true,
+            max_network_size: 10 * 1_048_576, // 10M
         }
     }
 }
diff --git a/beacon_node/beacon_chain/src/errors.rs b/beacon_node/beacon_chain/src/errors.rs
index 3d5aad3aa9c..cec72a5818a 100644
--- a/beacon_node/beacon_chain/src/errors.rs
+++ b/beacon_node/beacon_chain/src/errors.rs
@@ -185,6 +185,7 @@ pub enum BlockProductionError {
     GetPayloadFailed(execution_layer::Error),
     FailedToReadFinalizedBlock(store::Error),
     MissingFinalizedBlock(Hash256),
+    BlockTooLarge(usize),
 }
 
 easy_from_to!(BlockProcessingError, BlockProductionError);
diff --git a/beacon_node/beacon_chain/src/metrics.rs b/beacon_node/beacon_chain/src/metrics.rs
index 2967d40a18b..44b267647c5 100644
--- a/beacon_node/beacon_chain/src/metrics.rs
+++ b/beacon_node/beacon_chain/src/metrics.rs
@@ -107,6 +107,11 @@ lazy_static! {
         "Number of attestations in a block"
     );
 
+    pub static ref BLOCK_SIZE: Result<Histogram> = try_create_histogram(
+        "beacon_block_total_size",
+        "Size of a signed beacon block"
+    );
+
     /*
      * Unaggregated Attestation Verification
      */
diff --git a/beacon_node/lighthouse_network/src/lib.rs b/beacon_node/lighthouse_network/src/lib.rs
index 733dc72ab5b..b37b69dcfa6 100644
--- a/beacon_node/lighthouse_network/src/lib.rs
+++ b/beacon_node/lighthouse_network/src/lib.rs
@@ -16,6 +16,8 @@ pub mod rpc;
 mod service;
 pub mod types;
 
+pub use config::GOSSIP_MAX_SIZE;
+
 use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 use std::str::FromStr;
 
diff --git a/beacon_node/src/config.rs b/beacon_node/src/config.rs
index fc3ca2cc0b6..67fc910df75 100644
--- a/beacon_node/src/config.rs
+++ b/beacon_node/src/config.rs
@@ -471,6 +471,8 @@ pub fn get_config<E: EthSpec>(
         };
     }
 
+    client_config.chain.max_network_size = lighthouse_network::GOSSIP_MAX_SIZE;
+
     if cli_args.is_present("slasher") {
         let slasher_dir = if let Some(slasher_dir) = cli_args.value_of("slasher-dir") {
             PathBuf::from(slasher_dir)