diff --git a/.changeset/neat-cars-explain.md b/.changeset/neat-cars-explain.md
new file mode 100644
index 0000000000..466b9af019
--- /dev/null
+++ b/.changeset/neat-cars-explain.md
@@ -0,0 +1,5 @@
+---
+"hardhat": patch
+---
+
+fix hex of odd length for eth_getStorageAt call when forking arbitrum
diff --git a/packages/hardhat-core/src/internal/core/jsonrpc/types/base-types.ts b/packages/hardhat-core/src/internal/core/jsonrpc/types/base-types.ts
index 509d390b4b..f008700f5c 100644
--- a/packages/hardhat-core/src/internal/core/jsonrpc/types/base-types.ts
+++ b/packages/hardhat-core/src/internal/core/jsonrpc/types/base-types.ts
@@ -80,12 +80,20 @@ export function rpcQuantityToBN(quantity: string): BN {
 }
 
 export function numberToRpcQuantity(n: number | BN): string {
+  return numberToRpcQuantityWithLeadingZeros(n, false);
+}
+
+export function numberToRpcQuantityWithLeadingZeros(
+  n: number | BN,
+  leadingZeros: boolean
+): string {
   assertHardhatInvariant(
     typeof n === "number" || BN.isBN(n),
     "Expected number"
   );
 
-  return `0x${n.toString(16)}`;
+  const s = n.toString(16);
+  return leadingZeros ? `0x${s.length % 2 ? "0" : ""}${s}` : `0x${s}`;
 }
 
 /**
diff --git a/packages/hardhat-core/src/internal/hardhat-network/jsonrpc/client.ts b/packages/hardhat-core/src/internal/hardhat-network/jsonrpc/client.ts
index c69000a083..a5d9842921 100644
--- a/packages/hardhat-core/src/internal/hardhat-network/jsonrpc/client.ts
+++ b/packages/hardhat-core/src/internal/hardhat-network/jsonrpc/client.ts
@@ -4,7 +4,8 @@ import * as t from "io-ts";
 import path from "path";
 
 import {
-  numberToRpcQuantity,
+  numberToRpcQuantity, 
+  numberToRpcQuantityWithLeadingZeros,
   rpcData,
   rpcQuantity,
 } from "../../core/jsonrpc/types/base-types";
@@ -56,7 +57,7 @@ export class JsonRpcClient {
       "eth_getStorageAt",
       [
         address.toString(),
-        numberToRpcQuantity(position),
+        numberToRpcQuantityWithLeadingZeros(position, true),
         numberToRpcQuantity(blockNumber),
       ],
       rpcData,