diff --git a/solution/2700-2799/2785.Sort Vowels in a String/README.md b/solution/2700-2799/2785.Sort Vowels in a String/README.md
index edb9599ed0f8b..9680ee488c319 100644
--- a/solution/2700-2799/2785.Sort Vowels in a String/README.md	
+++ b/solution/2700-2799/2785.Sort Vowels in a String/README.md	
@@ -163,6 +163,34 @@ function sortVowels(s: string): string {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public string SortVowels(string s) {
+        List<char> vs = new List<char>();
+        char[] cs = s.ToCharArray();
+        foreach (char c in cs) {
+            if (IsVowel(c)) {
+                vs.Add(c);
+            }
+        }
+        vs.Sort();
+        for (int i = 0, j = 0; i < cs.Length; ++i) {
+            if (IsVowel(cs[i])) {
+                cs[i] = vs[j++];
+            }
+        }
+        return new string(cs);
+    }
+
+    public bool IsVowel(char c) {
+        c = char.ToLower(c);
+        return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
+    }
+}
+```
+
 ### **...**
 
 ```
diff --git a/solution/2700-2799/2785.Sort Vowels in a String/README_EN.md b/solution/2700-2799/2785.Sort Vowels in a String/README_EN.md
index f049e61593892..8355285940173 100644
--- a/solution/2700-2799/2785.Sort Vowels in a String/README_EN.md	
+++ b/solution/2700-2799/2785.Sort Vowels in a String/README_EN.md	
@@ -153,6 +153,34 @@ function sortVowels(s: string): string {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public string SortVowels(string s) {
+        List<char> vs = new List<char>();
+        char[] cs = s.ToCharArray();
+        foreach (char c in cs) {
+            if (IsVowel(c)) {
+                vs.Add(c);
+            }
+        }
+        vs.Sort();
+        for (int i = 0, j = 0; i < cs.Length; ++i) {
+            if (IsVowel(cs[i])) {
+                cs[i] = vs[j++];
+            }
+        }
+        return new string(cs);
+    }
+
+    public bool IsVowel(char c) {
+        c = char.ToLower(c);
+        return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
+    }
+}
+```
+
 ### **...**
 
 ```
diff --git a/solution/2700-2799/2785.Sort Vowels in a String/Solution.cs b/solution/2700-2799/2785.Sort Vowels in a String/Solution.cs
new file mode 100644
index 0000000000000..a115baf150316
--- /dev/null
+++ b/solution/2700-2799/2785.Sort Vowels in a String/Solution.cs	
@@ -0,0 +1,23 @@
+public class Solution {
+    public string SortVowels(string s) {
+        List<char> vs = new List<char>();
+        char[] cs = s.ToCharArray();
+        foreach (char c in cs) {
+            if (IsVowel(c)) {
+                vs.Add(c);
+            }
+        }
+        vs.Sort();
+        for (int i = 0, j = 0; i < cs.Length; ++i) {
+            if (IsVowel(cs[i])) {
+                cs[i] = vs[j++];
+            }
+        }
+        return new string(cs);
+    }
+
+    public bool IsVowel(char c) {
+        c = char.ToLower(c);
+        return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
+    }
+}