diff --git a/cs/single-number.cs b/cs/single-number.cs
new file mode 100644
index 0000000..4fd3137
--- /dev/null
+++ b/cs/single-number.cs
@@ -0,0 +1,5 @@
+public class Solution {
+    public int SingleNumber(int[] nums) {
+        return nums.Aggregate((x, y) => x ^ y);
+    }
+}