diff --git a/DIRECTORY.md b/DIRECTORY.md
index b3907e20..4152c54d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -242,6 +242,9 @@
     * [Sol1](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2015/sol1.c)
   * Problem 16
     * [Sol1](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2016/sol1.c)
+  * Problem 23
+    * [Sol1](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2023/sol1.c)
+    * [Sol2](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2023/sol2.c)
 
 ## Searching
   * [Binary Search](https://github.com/TheAlgorithms/C/blob/master/searching/Binary_Search.c)