diff --git a/typescript/0448-find-all-numbers-disappeared-in-an-array.ts b/typescript/0448-find-all-numbers-disappeared-in-an-array.ts
new file mode 100644
index 000000000..fe9ff5420
--- /dev/null
+++ b/typescript/0448-find-all-numbers-disappeared-in-an-array.ts
@@ -0,0 +1,16 @@
+function findDisappearedNumbers(nums: number[]): number[] {
+    for (const n of nums) {
+        let i = Math.abs(n) - 1;
+        nums[i] = -1 * Math.abs(nums[i]);
+    }
+
+    let res: number[] = [];
+
+    for (let [i, n] of nums.entries()) {
+        if (n > 0) {
+            res.push(i + 1);
+        }
+    }
+
+    return res;
+}