diff --git a/src/main/kotlin/binaryTree/PreorderTraverse.kt b/src/main/kotlin/binaryTree/PreorderTraverse.kt
new file mode 100644
index 0000000..57bc9e6
--- /dev/null
+++ b/src/main/kotlin/binaryTree/PreorderTraverse.kt
@@ -0,0 +1,24 @@
+package binaryTree
+
+/**
+ * This is the preorder traverse of binary tree
+ * @param root - root of TreeNode
+ * @see TreeNode - node has reference on left and right child
+ */
+
+
+fun preorderTraverse(root: TreeNode?): List<Int> {
+    root ?: return listOf()
+    val nodes = mutableListOf<Int>()
+
+    fun dfs(root: TreeNode?) {
+        root ?: return
+
+        nodes.add(root.value)
+        dfs(root.left)
+        dfs(root.right)
+    }
+    dfs(root)
+
+    return nodes
+}
\ No newline at end of file
diff --git a/src/main/kotlin/binaryTree/TreeNode.kt b/src/main/kotlin/binaryTree/TreeNode.kt
new file mode 100644
index 0000000..9cefde9
--- /dev/null
+++ b/src/main/kotlin/binaryTree/TreeNode.kt
@@ -0,0 +1,6 @@
+package binaryTree
+
+class TreeNode(val value: Int) {
+    var left: TreeNode? = null
+    var right: TreeNode? = null
+}
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diff --git a/src/test/kotlin/binaryTree/PreorderTraverseTest.kt b/src/test/kotlin/binaryTree/PreorderTraverseTest.kt
new file mode 100644
index 0000000..d37f3c9
--- /dev/null
+++ b/src/test/kotlin/binaryTree/PreorderTraverseTest.kt
@@ -0,0 +1,30 @@
+package binaryTree
+
+import org.junit.Assert.assertArrayEquals
+import org.junit.Test
+
+class PreorderTraverseTest {
+
+    @Test
+    fun `base_case`() {
+        val root = TreeNode(1)
+        root.left = TreeNode(2)
+        root.right = TreeNode(3)
+
+        val expected = listOf(1, 2, 3)
+        val res = preorderTraverse(root)
+
+        assertArrayEquals(expected.toIntArray(), res.toIntArray())
+    }
+
+
+    @Test
+    fun `empty_tree`() {
+        val root: TreeNode? = null
+
+        val expected = emptyList<Int>()
+        val res = preorderTraverse(root)
+
+        assertArrayEquals(expected.toIntArray(), res.toIntArray())
+    }
+}
\ No newline at end of file