diff --git a/cairo/ethereum/cancun/blocks.cairo b/cairo/ethereum/cancun/blocks.cairo
index 2339fb7f0..6b22384c1 100644
--- a/cairo/ethereum/cancun/blocks.cairo
+++ b/cairo/ethereum/cancun/blocks.cairo
@@ -2,7 +2,7 @@ from ethereum_types.numeric import U64, U256, Uint, bool
 from ethereum_types.bytes import Bytes, Bytes8, Bytes32, TupleBytes, TupleBytes32
 from ethereum.cancun.fork_types import Address, Bloom, Root
 from ethereum.crypto.hash import Hash32
-
+from ethereum.cancun.transactions_types import LegacyTransaction
 struct WithdrawalStruct {
     index: U64,
     validator_index: U64,
@@ -88,3 +88,41 @@ struct ReceiptStruct {
 struct Receipt {
     value: ReceiptStruct*,
 }
+
+struct UnionBytesLegacyTransactionEnum {
+    bytes: Bytes,
+    legacy: LegacyTransaction,
+}
+
+struct UnionBytesLegacyTransaction {
+    value: UnionBytesLegacyTransactionEnum*,
+}
+
+struct TupleUnionBytesLegacyTransactionStruct {
+    data: UnionBytesLegacyTransaction*,
+    len: felt,
+}
+
+struct TupleUnionBytesLegacyTransaction {
+    value: TupleUnionBytesLegacyTransactionStruct*,
+}
+
+struct BlockStruct {
+    header: Header,
+    transactions: TupleUnionBytesLegacyTransaction,
+    ommers: TupleHeader,
+    withdrawals: TupleWithdrawal,
+}
+
+struct Block {
+    value: BlockStruct*,
+}
+
+struct ListBlockStruct {
+    data: Block*,
+    len: felt,
+}
+
+struct ListBlock {
+    value: ListBlockStruct*,
+}
diff --git a/cairo/ethereum/cancun/fork.cairo b/cairo/ethereum/cancun/fork.cairo
index 12e7e1cd8..d57bbc85e 100644
--- a/cairo/ethereum/cancun/fork.cairo
+++ b/cairo/ethereum/cancun/fork.cairo
@@ -8,16 +8,28 @@ from starkware.cairo.common.cairo_builtins import (
 )
 from starkware.cairo.common.dict_access import DictAccess
 from starkware.cairo.common.math import assert_not_zero, split_felt, assert_le_felt
-from starkware.cairo.common.math_cmp import is_le
+from starkware.cairo.common.math_cmp import is_le, is_le_felt
 from starkware.cairo.common.registers import get_fp_and_pc
 
-from ethereum_rlp.rlp import Extended, ExtendedImpl, encode_receipt_to_buffer
+from ethereum_rlp.rlp import Extended, ExtendedImpl, encode_receipt_to_buffer, encode_header
 from ethereum_types.bytes import Bytes, Bytes0, BytesStruct, TupleBytes32
 from ethereum_types.numeric import Uint, bool, U256, U256Struct, U64
-from ethereum.cancun.blocks import Header, Receipt, ReceiptStruct, TupleLog, Log, TupleLogStruct
+from ethereum.cancun.blocks import (
+    Header,
+    Receipt,
+    ReceiptStruct,
+    TupleLog,
+    Log,
+    TupleLogStruct,
+    Block,
+    ListBlock,
+    TupleHeader,
+)
 from ethereum.cancun.bloom import logs_bloom
 from ethereum.cancun.fork_types import (
     Address,
+    ListHash32,
+    ListHash32Struct,
     OptionalAddress,
     SetAddress,
     SetAddressStruct,
@@ -65,11 +77,12 @@ from ethereum.cancun.vm.gas import (
     calculate_blob_gas_price,
 )
 from ethereum.cancun.vm.interpreter import process_message_call, MessageCallOutput
-from ethereum.crypto.hash import keccak256
+from ethereum.crypto.hash import keccak256, Hash32
 from ethereum.exceptions import OptionalEthereumException
 from ethereum.utils.numeric import (
     divmod,
     min,
+    is_zero,
     U256_add,
     U256__eq__,
     U256_from_felt,
@@ -89,6 +102,16 @@ const EMPTY_OMMER_HASH_LOW = 0xd312451b948a7413f0a142fd40d49347;
 const EMPTY_OMMER_HASH_HIGH = 0x1dcc4de8dec75d7aab85b567b6ccd41a;
 const VERSIONED_HASH_VERSION_KZG = 0x01;
 
+struct BlockChainStruct {
+    blocks: ListBlock,
+    state: State,
+    chain_id: U64,
+}
+
+struct BlockChain {
+    value: BlockChainStruct*,
+}
+
 func calculate_base_fee_per_gas{range_check_ptr}(
     block_gas_limit: Uint,
     parent_gas_limit: Uint,
@@ -732,3 +755,74 @@ func _check_versioned_hashes_version{range_check_ptr}(
 
     return ();
 }
+
+func get_last_256_block_hashes{
+    range_check_ptr, bitwise_ptr: BitwiseBuiltin*, keccak_ptr: KeccakBuiltin*
+}(chain: BlockChain) -> ListHash32 {
+    alloc_locals;
+
+    // If no blocks, return empty array
+    if (chain.value.blocks.value.len == 0) {
+        let (empty_hashes_alloc: Hash32*) = alloc();
+        tempvar empty_hashes = ListHash32(new ListHash32Struct(data=empty_hashes_alloc, len=0));
+        return empty_hashes;
+    }
+
+    // Get last 255 blocks or all blocks if less than 255
+    let is_le_255 = is_le(chain.value.blocks.value.len, 255);
+    if (is_le_255 != FALSE) {
+        tempvar start_idx = 0;
+    } else {
+        tempvar start_idx = chain.value.blocks.value.len - 255;
+    }
+    tempvar recent_blocks_len = chain.value.blocks.value.len - start_idx;
+
+    // Allocate list for hashes
+    let (hashes: Hash32*) = alloc();
+
+    // Get parent hashes from recent blocks
+    _get_parent_hashes{hashes=hashes}(
+        chain.value.blocks.value.data + start_idx, recent_blocks_len, 0
+    );
+
+    // Add hash of most recent block
+    let most_recent_block: Block* = chain.value.blocks.value.data + chain.value.blocks.value.len -
+        1;
+    let most_recent_hash = keccak256_header(most_recent_block.value.header);
+    assert hashes[recent_blocks_len] = most_recent_hash;
+    tempvar list_hash_32 = ListHash32(new ListHash32Struct(data=hashes, len=recent_blocks_len + 1));
+    return list_hash_32;
+}
+
+// Helper function to get parent hashes using a loop
+func _get_parent_hashes{hashes: Hash32*}(blocks: Block*, len: felt, idx: felt) {
+    tempvar idx = idx;
+
+    loop:
+    let idx = [ap - 1];
+
+    let end_loop = is_zero(idx - len);
+    jmp end if end_loop != 0;
+
+    // Get block at current index and store parent hash
+    let block: Block* = blocks + idx;
+    assert hashes[idx] = block.value.header.value.parent_hash;
+
+    tempvar idx = idx + 1;
+
+    jmp loop;
+
+    end:
+    return ();
+}
+
+// Helper to compute header hash
+func keccak256_header{range_check_ptr, bitwise_ptr: BitwiseBuiltin*, keccak_ptr: KeccakBuiltin*}(
+    header: Header
+) -> Hash32 {
+    // First RLP encode the header
+    let encoded_header = encode_header(header);
+
+    // Then compute keccak256 of the encoded bytes
+    return keccak256(encoded_header);
+}
diff --git a/cairo/tests/ethereum/cancun/test_fork.py b/cairo/tests/ethereum/cancun/test_fork.py
index d312bf208..182a03fa5 100644
--- a/cairo/tests/ethereum/cancun/test_fork.py
+++ b/cairo/tests/ethereum/cancun/test_fork.py
@@ -8,18 +8,20 @@
 from hypothesis import strategies as st
 from hypothesis.strategies import composite, integers
 
-from ethereum.cancun.blocks import Header, Log
+from ethereum.cancun.blocks import Block, Header, Log
 from ethereum.cancun.fork import (
     GAS_LIMIT_ADJUSTMENT_FACTOR,
+    BlockChain,
     calculate_base_fee_per_gas,
     check_gas_limit,
     check_transaction,
+    get_last_256_block_hashes,
     make_receipt,
     process_transaction,
     validate_header,
 )
 from ethereum.cancun.fork_types import Address
-from ethereum.cancun.state import set_account
+from ethereum.cancun.state import State, set_account
 from ethereum.cancun.transactions import (
     AccessListTransaction,
     BlobTransaction,
@@ -259,3 +261,12 @@ def test_check_transaction(
             state, tx, gas_available, chain_id, base_fee_per_gas, excess_blob_gas
         )
         assert cairo_state == state
+
+    @given(blocks=st.lists(st.builds(Block), max_size=300))
+    def test_get_last_256_block_hashes(self, cairo_run, blocks):
+        chain = BlockChain(blocks=blocks, state=State(), chain_id=U64(1))
+
+        py_result = get_last_256_block_hashes(chain)
+        cairo_result = cairo_run("get_last_256_block_hashes", chain)
+
+        assert py_result == cairo_result
diff --git a/cairo/tests/test_serde.cairo b/cairo/tests/test_serde.cairo
index 7313c2b15..7bf289956 100644
--- a/cairo/tests/test_serde.cairo
+++ b/cairo/tests/test_serde.cairo
@@ -30,6 +30,7 @@ from ethereum.cancun.blocks import (
     Log,
     TupleLog,
     Receipt,
+    ListBlock,
 )
 
 from ethereum.cancun.transactions_types import (
@@ -48,3 +49,4 @@ from ethereum.exceptions import EthereumException
 from ethereum.cancun.state import TransientStorage
 from ethereum.cancun.vm import Environment
 from ethereum.cancun.vm.interpreter import MessageCallOutput
+from ethereum.cancun.fork import BlockChain
diff --git a/cairo/tests/test_serde.py b/cairo/tests/test_serde.py
index 27472c2c9..e43a57207 100644
--- a/cairo/tests/test_serde.py
+++ b/cairo/tests/test_serde.py
@@ -9,7 +9,8 @@
 from starkware.cairo.lang.vm.memory_dict import MemoryDict
 from starkware.cairo.lang.vm.memory_segments import MemorySegmentManager
 
-from ethereum.cancun.blocks import Header, Log, Receipt, Withdrawal
+from ethereum.cancun.blocks import Block, Header, Log, Receipt, Withdrawal
+from ethereum.cancun.fork import BlockChain
 from ethereum.cancun.fork_types import Account, Address, Bloom, Root, VersionedHash
 from ethereum.cancun.state import State, TransientStorage
 from ethereum.cancun.transactions import (
@@ -261,6 +262,11 @@ def test_type(
             List[Tuple[U256, U256]],
             ExtendMemory,
             MessageCallOutput,
+            Union[Bytes, LegacyTransaction],
+            Tuple[Union[Bytes, LegacyTransaction], ...],
+            Block,
+            List[Block],
+            BlockChain,
         ],
     ):
         assume(no_empty_sequence(b))
diff --git a/cairo/tests/utils/args_gen.py b/cairo/tests/utils/args_gen.py
index e5d656eb6..b75d2af20 100644
--- a/cairo/tests/utils/args_gen.py
+++ b/cairo/tests/utils/args_gen.py
@@ -104,7 +104,8 @@
 from cairo_addons.vm import DictTracker as RustDictTracker
 from cairo_addons.vm import MemorySegmentManager as RustMemorySegmentManager
 from cairo_addons.vm import Relocatable as RustRelocatable
-from ethereum.cancun.blocks import Header, Log, Receipt, Withdrawal
+from ethereum.cancun.blocks import Block, Header, Log, Receipt, Withdrawal
+from ethereum.cancun.fork import BlockChain
 from ethereum.cancun.fork_types import Account, Address, Bloom, Root, VersionedHash
 from ethereum.cancun.state import State, TransientStorage
 from ethereum.cancun.transactions import (
@@ -448,6 +449,15 @@ def __eq__(self, other):
     ("ethereum", "cancun", "blocks", "Log"): Log,
     ("ethereum", "cancun", "blocks", "TupleLog"): Tuple[Log, ...],
     ("ethereum", "cancun", "blocks", "Receipt"): Receipt,
+    ("ethereum", "cancun", "blocks", "UnionBytesLegacyTransaction"): Union[
+        Bytes, LegacyTransaction
+    ],
+    ("ethereum", "cancun", "blocks", "TupleUnionBytesLegacyTransaction"): Tuple[
+        Union[Bytes, LegacyTransaction], ...
+    ],
+    ("ethereum", "cancun", "blocks", "Block"): Block,
+    ("ethereum", "cancun", "blocks", "ListBlock"): List[Block],
+    ("ethereum", "cancun", "fork", "BlockChain"): BlockChain,
     ("ethereum", "cancun", "fork_types", "Address"): Address,
     ("ethereum", "cancun", "fork_types", "SetAddress"): Set[Address],
     ("ethereum", "cancun", "fork_types", "Root"): Root,