diff --git a/packages/core/src/models/ergoBox.spec.ts b/packages/core/src/models/ergoBox.spec.ts
index 55888f45..1f1e7894 100644
--- a/packages/core/src/models/ergoBox.spec.ts
+++ b/packages/core/src/models/ergoBox.spec.ts
@@ -1,6 +1,7 @@
 import {
   invalidBoxesMock,
   manyTokensBoxesMock,
+  outOfOrderRegistersBox,
   regularBoxesMock,
   validBoxesMock
 } from "../tests/mocks/mockBoxes";
@@ -36,6 +37,8 @@ describe("Validation", () => {
     for (const box of validBoxesMock) {
       expect(new ErgoBox(box).isValid()).toBeTruthy();
     }
+
+    expect(new ErgoBox(outOfOrderRegistersBox).isValid()).toBeTruthy();
   });
 
   it("Should not validate invalid boxes", () => {
diff --git a/packages/core/src/serializer/sigma/boxSerializer.ts b/packages/core/src/serializer/sigma/boxSerializer.ts
index b4bea919..dfbc4cec 100644
--- a/packages/core/src/serializer/sigma/boxSerializer.ts
+++ b/packages/core/src/serializer/sigma/boxSerializer.ts
@@ -30,12 +30,13 @@ function serializeTokens(tokens: TokenAmount<Amount>[]): Uint8Array {
 }
 
 function serializeRegisters(registers: NonMandatoryRegisters): Uint8Array {
-  const keys = Object.keys(registers);
+  let keys = Object.keys(registers);
   if (isEmpty(keys)) {
     return Uint8Array.from([0]);
   }
 
   const serializedRegisters: Uint8Array[] = [];
+  keys = keys.sort();
   for (const key of keys) {
     const val = registers[key as keyof NonMandatoryRegisters];
     if (isDefined(val)) {
diff --git a/packages/core/src/tests/mocks/mockBoxes.ts b/packages/core/src/tests/mocks/mockBoxes.ts
index e26a47e4..4f1d1e9e 100644
--- a/packages/core/src/tests/mocks/mockBoxes.ts
+++ b/packages/core/src/tests/mocks/mockBoxes.ts
@@ -1695,3 +1695,26 @@ export const invalidBoxesMock = [
     }
   }
 ];
+
+export const outOfOrderRegistersBox = {
+  boxId: "d9ee4ee66b95f4676c74d7d9c9dca32010edb73cfe648a6ced1d678df981ca83",
+  value: "1100000000",
+  ergoTree:
+    "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",
+  assets: [
+    {
+      tokenId: "1ffa93059d1d3579de91c24d5246c6da0823703bd4a9aeff2b5f81fee71bf3e8",
+      amount: "1"
+    }
+  ],
+  additionalRegisters: {
+    R5: "5980a5e8deb161c0c9d1aeb261",
+    R6: "110280a8d6b9078084af5f",
+    R4: "0e240008cd0333099ca68e2b307344ae521eb0f418c7affed0bf7f973c5a10886182345ce2e0",
+    R8: "0e240008cd0333099ca68e2b307344ae521eb0f418c7affed0bf7f973c5a10886182345ce2e0",
+    R7: "0e00"
+  },
+  creationHeight: 218333,
+  transactionId: "63661fccf4621fc9c9864f2cf5bb6a14ff7784156504101ac4199dd400196d82",
+  index: 0
+};