diff --git a/problems/0236.二叉树的最近公共祖先.md b/problems/0236.二叉树的最近公共祖先.md
index edb5ea3e..0e99f1c2 100644
--- a/problems/0236.二叉树的最近公共祖先.md
+++ b/problems/0236.二叉树的最近公共祖先.md
@@ -431,6 +431,19 @@ impl Solution {
     }
 }
 ```
+### C#
+```C#
+public TreeNode LowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q)
+{
+    if (root == null || root == p || root == q) return root;
+    TreeNode left = LowestCommonAncestor(root.left, p, q);
+    TreeNode right = LowestCommonAncestor(root.right, p, q);
+    if (left != null && right != null) return root;
+    if (left == null && right != null) return right;
+    if (left != null && right == null) return left;
+    return null;
+}
+```
 
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