diff --git a/.changeset/tender-spoons-burn.md b/.changeset/tender-spoons-burn.md
new file mode 100644
index 000000000..2347ef7bc
--- /dev/null
+++ b/.changeset/tender-spoons-burn.md
@@ -0,0 +1,5 @@
+---
+'graphql-scalars': patch
+---
+
+Fix BigInt handling
diff --git a/src/scalars/BigInt.ts b/src/scalars/BigInt.ts
index 4a7ec325f..802034ef4 100644
--- a/src/scalars/BigInt.ts
+++ b/src/scalars/BigInt.ts
@@ -80,7 +80,7 @@ export const GraphQLBigIntConfig: GraphQLScalarTypeConfig<
     if (inputValue.toString() !== bigint.toString()) {
       throw createGraphQLError(`BigInt cannot represent value: ${inputValue}`);
     }
-    if (!isSafeInteger(bigint) && !isBigIntSerializable()) {
+    if (isSafeInteger(bigint) && !isBigIntSerializable()) {
       return Number(bigint.toString());
     }
     return bigint;
@@ -96,7 +96,7 @@ export const GraphQLBigIntConfig: GraphQLScalarTypeConfig<
     if (strOrBooleanValue.toString() !== bigint.toString()) {
       throw createGraphQLError(`BigInt cannot represent value: ${strOrBooleanValue}`);
     }
-    if (!isSafeInteger(bigint) && !isBigIntSerializable()) {
+    if (isSafeInteger(bigint) && !isBigIntSerializable()) {
       return Number(bigint.toString());
     }
     return bigint;