diff --git a/crates/napi/src/bindgen_runtime/js_values/bigint.rs b/crates/napi/src/bindgen_runtime/js_values/bigint.rs
index 67256488..5261e137 100644
--- a/crates/napi/src/bindgen_runtime/js_values/bigint.rs
+++ b/crates/napi/src/bindgen_runtime/js_values/bigint.rs
@@ -205,6 +205,15 @@ impl ToNapiValue for isize {
   }
 }
 
+impl From<i64> for BigInt {
+  fn from(val: i64) -> Self {
+    BigInt {
+      sign_bit: val < 0,
+      words: vec![val as u64],
+    }
+  }
+}
+
 impl From<u64> for BigInt {
   fn from(val: u64) -> Self {
     BigInt {
@@ -213,3 +222,24 @@ impl From<u64> for BigInt {
     }
   }
 }
+
+impl From<i128> for BigInt {
+  fn from(val: i128) -> Self {
+    let sign_bit = val < 0;
+    let words = (if sign_bit { -val } else { val }).to_ne_bytes();
+    BigInt {
+      sign_bit,
+      words: unsafe { std::slice::from_raw_parts(words.as_ptr() as *mut _, 2).to_vec() },
+    }
+  }
+}
+
+impl From<u128> for BigInt {
+  fn from(val: u128) -> Self {
+    let words = val.to_ne_bytes();
+    BigInt {
+      sign_bit: false,
+      words: unsafe { std::slice::from_raw_parts(words.as_ptr() as *mut _, 2).to_vec() },
+    }
+  }
+}
diff --git a/examples/napi/__test__/typegen.spec.ts.md b/examples/napi/__test__/typegen.spec.ts.md
index d104c6fb..76385fc9 100644
--- a/examples/napi/__test__/typegen.spec.ts.md
+++ b/examples/napi/__test__/typegen.spec.ts.md
@@ -34,6 +34,8 @@ Generated by [AVA](https://avajs.dev).
     export function createBigInt(): bigint␊
     export function createBigIntI64(): bigint␊
     export function bigintGetU64AsString(bi: bigint): string␊
+    export function bigintFromI64(): bigint␊
+    export function bigintFromI128(): bigint␊
     export function getCwd(callback: (arg0: string) => void): void␊
     export function optionEnd(callback: (arg0: string, arg1?: string | undefined | null) => void): void␊
     export function optionStart(callback: (arg0: string | undefined | null, arg1: string) => void): void␊
diff --git a/examples/napi/__test__/typegen.spec.ts.snap b/examples/napi/__test__/typegen.spec.ts.snap
index 22ff5dba..375b4dee 100644
Binary files a/examples/napi/__test__/typegen.spec.ts.snap and b/examples/napi/__test__/typegen.spec.ts.snap differ
diff --git a/examples/napi/__test__/values.spec.ts b/examples/napi/__test__/values.spec.ts
index b6f38072..1747067c 100644
--- a/examples/napi/__test__/values.spec.ts
+++ b/examples/napi/__test__/values.spec.ts
@@ -114,6 +114,8 @@ import {
   plusOne,
   Width,
   captureErrorInCallback,
+  bigintFromI128,
+  bigintFromI64,
 } from '../'
 
 test('export const', (t) => {
@@ -679,6 +681,11 @@ BigIntTest('js mod test', (t) => {
   t.is(xx3.digest(), BigInt('1116'))
 })
 
+BigIntTest('from i128 i64', (t) => {
+  t.is(bigintFromI64(), BigInt('100'))
+  t.is(bigintFromI128(), BigInt('-100'))
+})
+
 const Napi4Test = Number(process.versions.napi) >= 4 ? test : test.skip
 
 Napi4Test('call thread safe function', (t) => {
diff --git a/examples/napi/index.d.ts b/examples/napi/index.d.ts
index 70132707..aab94c85 100644
--- a/examples/napi/index.d.ts
+++ b/examples/napi/index.d.ts
@@ -24,6 +24,8 @@ export function bigintAdd(a: bigint, b: bigint): bigint
 export function createBigInt(): bigint
 export function createBigIntI64(): bigint
 export function bigintGetU64AsString(bi: bigint): string
+export function bigintFromI64(): bigint
+export function bigintFromI128(): bigint
 export function getCwd(callback: (arg0: string) => void): void
 export function optionEnd(callback: (arg0: string, arg1?: string | undefined | null) => void): void
 export function optionStart(callback: (arg0: string | undefined | null, arg1: string) => void): void
diff --git a/examples/napi/src/bigint.rs b/examples/napi/src/bigint.rs
index 6962c76e..b6e30b67 100644
--- a/examples/napi/src/bigint.rs
+++ b/examples/napi/src/bigint.rs
@@ -22,3 +22,13 @@ fn create_big_int_i64() -> i64n {
 pub fn bigint_get_u64_as_string(bi: BigInt) -> String {
   bi.get_u64().1.to_string()
 }
+
+#[napi]
+pub fn bigint_from_i64() -> BigInt {
+  BigInt::from(100i64)
+}
+
+#[napi]
+pub fn bigint_from_i128() -> BigInt {
+  BigInt::from(-100i128)
+}