diff --git a/specs/merge/beacon-chain.md b/specs/merge/beacon-chain.md
index 1b56ca37c..f5977db5e 100644
--- a/specs/merge/beacon-chain.md
+++ b/specs/merge/beacon-chain.md
@@ -144,8 +144,6 @@ class BeaconState(Container):
 
 #### `ExecutionPayload`
 
-*Note*: The `base_fee_per_gas` field is serialized in little-endian.
-
 ```python
 class ExecutionPayload(Container):
     # Execution block header fields
@@ -160,7 +158,7 @@ class ExecutionPayload(Container):
     gas_used: uint64
     timestamp: uint64
     extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
-    base_fee_per_gas: Bytes32  # base fee introduced in EIP-1559, little-endian serialized
+    base_fee_per_gas: uint256
     # Extra payload fields
     block_hash: Hash32  # Hash of execution block
     transactions: List[Transaction, MAX_TRANSACTIONS_PER_PAYLOAD]
@@ -182,7 +180,7 @@ class ExecutionPayloadHeader(Container):
     gas_used: uint64
     timestamp: uint64
     extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
-    base_fee_per_gas: Bytes32
+    base_fee_per_gas: uint256
     # Extra payload fields
     block_hash: Hash32  # Hash of execution block
     transactions_root: Root
diff --git a/tests/core/pyspec/eth2spec/test/helpers/genesis.py b/tests/core/pyspec/eth2spec/test/helpers/genesis.py
index cd96c8168..408295072 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/genesis.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/genesis.py
@@ -33,7 +33,7 @@ def get_sample_genesis_execution_payload_header(spec,
         random=eth1_block_hash,
         block_number=0,
         gas_limit=30000000,
-        base_fee_per_gas=spec.Bytes32('0x00ca9a3b00000000000000000000000000000000000000000000000000000000'),
+        base_fee_per_gas=1000000000,
         block_hash=eth1_block_hash,
         transactions_root=spec.Root(b'\x56' * 32),
     )