diff --git a/common/changes/@subsquid/evm-processor/master_2023-07-20-23-45.json b/common/changes/@subsquid/evm-processor/master_2023-07-20-23-45.json
new file mode 100644
index 000000000..0a112c8f3
--- /dev/null
+++ b/common/changes/@subsquid/evm-processor/master_2023-07-20-23-45.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@subsquid/evm-processor",
+      "comment": "fix `TypeError: Cannot convert null to a BigInt` during data mapping",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@subsquid/evm-processor"
+}
\ No newline at end of file
diff --git a/evm/evm-processor/src/ds-archive/mapping.ts b/evm/evm-processor/src/ds-archive/mapping.ts
index 157521888..496226f2a 100644
--- a/evm/evm-processor/src/ds-archive/mapping.ts
+++ b/evm/evm-processor/src/ds-archive/mapping.ts
@@ -104,6 +104,7 @@ function mapBlockHeader(src: gw.Block): BlockHeader<AllFields> {
 
     let key: keyof gw.Block
     for (key in src) {
+        if (src[key] == null) continue
         switch(key) {
             case 'number':
                 header.height = src.number
@@ -135,6 +136,7 @@ function mapTransaction(block: BlockHeader<AllFields>, src: gw.Transaction): Tra
 
     let key: keyof gw.Transaction
     for (key in src) {
+        if (src[key] == null) continue
         switch(key) {
             case 'gas':
             case 'gasPrice':