diff --git a/Leetcode/209.minimum-size-subarray-sum.ts b/Leetcode/209.minimum-size-subarray-sum.ts
new file mode 100644
index 0000000..d6a2aab
--- /dev/null
+++ b/Leetcode/209.minimum-size-subarray-sum.ts
@@ -0,0 +1,24 @@
+/*
+ * [209] Minimum Size Subarray Sum
+ */
+
+function minSubArrayLen(target: number, nums: number[]): number {
+  let minLength = Infinity;
+  let left = 0,
+    right = left;
+  let sum = 0;
+
+  while (right < nums.length) {
+    if (sum < target) {
+      sum += nums[right];
+      right++;
+    }
+    while (sum >= target) {
+      minLength = Math.min(minLength, right - left);
+      sum -= nums[left];
+      left++;
+    }
+  }
+
+  return minLength === Infinity ? 0 : minLength;
+}