diff --git a/packages/relay/src/lib/eth.ts b/packages/relay/src/lib/eth.ts
index 122f9e0d60..0fca0b0ca9 100644
--- a/packages/relay/src/lib/eth.ts
+++ b/packages/relay/src/lib/eth.ts
@@ -702,7 +702,7 @@ export class EthImpl implements Eth {
    * @rpcParamValidationRules Applies JSON-RPC parameter validation according to the API specification
    *
    * @param {string} account The account to get the balance from
-   * @param {string | null} blockNumberOrTagOrHash The block number or tag or hash to get the balance from
+   * @param {string} blockNumberOrTagOrHash The block number or tag or hash to get the balance from
    * @param {RequestDetails} requestDetails The request details for logging and tracking
    * @returns {Promise<string>} A promise that resolves to the balance of the account in hexadecimal format.
    */
@@ -714,11 +714,7 @@ export class EthImpl implements Eth {
   @cache(CacheService.getInstance(CACHE_LEVEL.L1), {
     skipParams: [{ index: '1', value: constants.NON_CACHABLE_BLOCK_PARAMS }],
   })
-  async getBalance(
-    account: string,
-    blockNumberOrTagOrHash: string | null,
-    requestDetails: RequestDetails,
-  ): Promise<string> {
+  async getBalance(account: string, blockNumberOrTagOrHash: string, requestDetails: RequestDetails): Promise<string> {
     return this.accountService.getBalance(account, blockNumberOrTagOrHash, requestDetails);
   }
 
diff --git a/packages/relay/src/lib/services/ethService/accountService/AccountService.ts b/packages/relay/src/lib/services/ethService/accountService/AccountService.ts
index 5786767f3d..308d70d9ed 100644
--- a/packages/relay/src/lib/services/ethService/accountService/AccountService.ts
+++ b/packages/relay/src/lib/services/ethService/accountService/AccountService.ts
@@ -91,12 +91,12 @@ export class AccountService implements IAccountService {
    * Current implementation does not yet utilize blockNumber
    *
    * @param {string} account The account to get the balance from
-   * @param {string | null} blockNumberOrTagOrHash The block number or tag or hash to get the balance from
+   * @param {string} blockNumberOrTagOrHash The block number or tag or hash to get the balance from
    * @param {RequestDetails} requestDetails The request details for logging and tracking
    */
   public async getBalance(
     account: string,
-    blockNumberOrTagOrHash: string | null,
+    blockNumberOrTagOrHash: string,
     requestDetails: RequestDetails,
   ): Promise<string> {
     const requestIdPrefix = requestDetails.formattedRequestId;
@@ -174,7 +174,7 @@ export class AccountService implements IAccountService {
    * @param requestDetails
    * @private
    */
-  private async extractBlockNumberAndTimestamp(blockNumberOrTagOrHash: string | null, requestDetails: RequestDetails) {
+  private async extractBlockNumberAndTimestamp(blockNumberOrTagOrHash: string, requestDetails: RequestDetails) {
     let latestBlock: LatestBlockNumberTimestamp;
     const latestBlockTolerance = 1;
     let blockHashNumber, isHash;
@@ -192,7 +192,7 @@ export class AccountService implements IAccountService {
       latestBlock = await this.blockNumberTimestamp(constants.ETH_GET_BALANCE, requestDetails);
     }
 
-    if (blockNumberOrTagOrHash != null && blockNumberOrTagOrHash.length > 32) {
+    if (blockNumberOrTagOrHash.length > 32) {
       isHash = true;
       blockHashNumber = await this.mirrorNodeClient.getBlock(blockNumberOrTagOrHash, requestDetails);
     }
diff --git a/packages/relay/src/lib/services/ethService/accountService/IAccountService.ts b/packages/relay/src/lib/services/ethService/accountService/IAccountService.ts
index 32ab9fd767..df11f98fa3 100644
--- a/packages/relay/src/lib/services/ethService/accountService/IAccountService.ts
+++ b/packages/relay/src/lib/services/ethService/accountService/IAccountService.ts
@@ -10,9 +10,5 @@ export interface IAccountService {
     requestDetails: RequestDetails,
   ) => Promise<string | JsonRpcError>;
 
-  getBalance: (
-    account: string,
-    blockNumberOrTagOrHash: string | null,
-    requestDetails: RequestDetails,
-  ) => Promise<string>;
+  getBalance: (account: string, blockNumberOrTagOrHash: string, requestDetails: RequestDetails) => Promise<string>;
 }
diff --git a/packages/relay/tests/lib/eth/eth_getBalance.spec.ts b/packages/relay/tests/lib/eth/eth_getBalance.spec.ts
index 040aa9bb3a..60068283bb 100644
--- a/packages/relay/tests/lib/eth/eth_getBalance.spec.ts
+++ b/packages/relay/tests/lib/eth/eth_getBalance.spec.ts
@@ -59,7 +59,7 @@ describe('@ethGetBalance using MirrorNode', async function () {
     restMock.onGet(BLOCKS_LIMIT_ORDER_URL).reply(200, JSON.stringify(MOCK_BLOCK_NUMBER_1000_RES));
     restMock.onGet(`accounts/${CONTRACT_ADDRESS_1}?limit=100`).reply(200, JSON.stringify(MOCK_BALANCE_RES));
 
-    const resBalance = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resBalance = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
     expect(resBalance).to.equal(DEF_HEX_BALANCE);
   });
 
@@ -67,13 +67,13 @@ describe('@ethGetBalance using MirrorNode', async function () {
     restMock.onGet(BLOCKS_LIMIT_ORDER_URL).reply(200, JSON.stringify(MOCK_BLOCK_NUMBER_1000_RES));
     restMock.onGet(`accounts/${CONTRACT_ADDRESS_1}?limit=100`).reply(200, JSON.stringify(MOCK_BALANCE_RES));
 
-    const resBalance = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resBalance = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
     expect(resBalance).to.equal(DEF_HEX_BALANCE);
 
     // next call should use cache
     restMock.onGet(`accounts/${CONTRACT_ADDRESS_1}?limit=100`).reply(404, {});
 
-    const resBalanceCached = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resBalanceCached = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
     expect(resBalanceCached).to.equal(resBalance);
 
     // Third call should return new number using mirror node
@@ -91,7 +91,7 @@ describe('@ethGetBalance using MirrorNode', async function () {
     // expire cache, instead of waiting for ttl we clear it to simulate expiry faster.
     await cacheService.clear(requestDetails);
 
-    const resBalanceNew = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resBalanceNew = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
     expect(newBalanceHex).to.equal(resBalanceNew);
   });
 
@@ -162,7 +162,7 @@ describe('@ethGetBalance using MirrorNode', async function () {
     restMock.onGet(`contracts/${CONTRACT_ADDRESS_1}`).reply(200, JSON.stringify(null));
     restMock.onGet(`accounts/${CONTRACT_ADDRESS_1}?limit=100`).reply(404, JSON.stringify(NOT_FOUND_RES));
 
-    const resBalance = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resBalance = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
     expect(resBalance).to.equal(constants.ZERO_HEX);
   });
 
@@ -170,11 +170,11 @@ describe('@ethGetBalance using MirrorNode', async function () {
     restMock.onGet(BLOCKS_LIMIT_ORDER_URL).reply(200, JSON.stringify(MOCK_BLOCK_NUMBER_1000_RES));
     restMock.onGet(`accounts/${CONTRACT_ADDRESS_1}?limit=100`).reply(200, JSON.stringify(MOCK_BALANCE_RES));
 
-    const resNoCache = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resNoCache = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
 
     restMock.onGet(`accounts/${CONTRACT_ADDRESS_1}?limit=100`).reply(404, NOT_FOUND_RES);
 
-    const resCached = await ethImpl.getBalance(CONTRACT_ADDRESS_1, null, requestDetails);
+    const resCached = await ethImpl.getBalance(CONTRACT_ADDRESS_1, 'latest', requestDetails);
     expect(resNoCache).to.equal(DEF_HEX_BALANCE);
     expect(resCached).to.equal(DEF_HEX_BALANCE);
   });