diff --git a/#442/kotlin/Solution.kt b/#442/kotlin/Solution.kt
new file mode 100644
index 0000000..f80235d
--- /dev/null
+++ b/#442/kotlin/Solution.kt
@@ -0,0 +1,18 @@
+/**
+ * https://leetcode.com/problems/find-all-duplicates-in-an-array/
+ */
+
+class Solution {
+    fun findDuplicates(nums: IntArray): List<Int> {
+        val result: MutableList<Int> = ArrayList<Int>()
+        val temp: MutableList<Int> = ArrayList<Int>()
+        for (i in nums) {
+            if (temp.contains(i)) {
+                result.add(i)
+            } else {
+                temp.add(i)
+            }
+        }
+        return result
+    }
+}