diff --git a/packages/web3-eth-contract/test/integration/contract_estimateGas_without_0x.test.ts b/packages/web3-eth-contract/test/integration/contract_estimateGas_without_0x.test.ts
new file mode 100644
index 00000000000..91d484665eb
--- /dev/null
+++ b/packages/web3-eth-contract/test/integration/contract_estimateGas_without_0x.test.ts
@@ -0,0 +1,73 @@
+/*
+This file is part of web3.js.
+
+web3.js is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+web3.js is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import { ETH_DATA_FORMAT } from 'web3-types';
+import { Contract } from '../../src';
+import { getSystemTestProvider, createTempAccount } from '../fixtures/system_test_utils';
+
+describe('contract', () => {
+	// Create a new contract object using the ABI and bytecode
+	const abi = [
+		{
+			inputs: [{ internalType: 'uint256', name: '_myNumber', type: 'uint256' }],
+			stateMutability: 'nonpayable',
+			type: 'constructor',
+		},
+		{
+			inputs: [],
+			name: 'myNumber',
+			outputs: [{ internalType: 'uint256', name: '', type: 'uint256' }],
+			stateMutability: 'view',
+			type: 'function',
+		},
+		{
+			inputs: [{ internalType: 'uint256', name: '_myNumber', type: 'uint256' }],
+			name: 'setMyNumber',
+			outputs: [],
+			stateMutability: 'nonpayable',
+			type: 'function',
+		},
+	];
+	let acc: { address: string; privateKey: string };
+	let contract: Contract<typeof abi>;
+
+	beforeEach(async () => {
+		acc = await createTempAccount();
+	});
+
+	it('should be able to add `data` input without `0x` prefix', async () => {
+		contract = new Contract(abi, undefined, {
+			provider: getSystemTestProvider(),
+		});
+
+		const myContract = contract.deploy({
+			data: '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',
+			// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+			// @ts-expect-error
+			arguments: [1],
+		});
+
+		const gas = await myContract.estimateGas(
+			{
+				from: acc.address,
+			},
+			ETH_DATA_FORMAT,
+		);
+		expect(gas).toBeDefined();
+		expect(gas).toMatch(/0[xX][0-9a-fA-F]/i);
+	});
+});
diff --git a/packages/web3-utils/src/converters.ts b/packages/web3-utils/src/converters.ts
index ed0c89d1c33..e1ca62930ff 100644
--- a/packages/web3-utils/src/converters.ts
+++ b/packages/web3-utils/src/converters.ts
@@ -23,6 +23,7 @@ import {
 	isHex,
 	isHexStrict,
 	isNullish,
+	isInt,
 	utils as validatorUtils,
 	validator,
 } from 'web3-validator';
@@ -365,6 +366,9 @@ export const toHex = (
 		if (isHexStrict(value)) {
 			return returnType ? 'bytes' : value;
 		}
+		if (isHex(value) && !isInt(value)) {
+			return returnType ? 'bytes' : `0x${value}`;
+		}
 
 		if (!Number.isFinite(value)) {
 			return returnType ? 'string' : utf8ToHex(value);
diff --git a/packages/web3-utils/test/fixtures/converters.ts b/packages/web3-utils/test/fixtures/converters.ts
index b99efa1baea..ed3f7bb9274 100644
--- a/packages/web3-utils/test/fixtures/converters.ts
+++ b/packages/web3-utils/test/fixtures/converters.ts
@@ -234,6 +234,7 @@ export const toHexValidData: [Numbers | Bytes | Address | boolean, [HexString, V
 		['0x72fdb1c1ddd4c67804f42b93de95cf6a8c51d2d1', 'address'],
 	],
 	['-0x01', ['-0x1', 'int256']],
+	['123c', ['0x123c', 'bytes']],
 ];
 
 export const toHexInvalidData: [any, string][] = [