diff --git a/DIRECTORY.md b/DIRECTORY.md
index 626c5c63..e67ff0b1 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -256,6 +256,8 @@
     * [Sol2](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2023/sol2.c)
   * Problem 25
     * [Sol1](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2025/sol1.c)
+  * Problem 26
+    * [Sol1](https://github.com/TheAlgorithms/C/blob/master/project_euler/Problem%2026/sol1.c)
 
 ## Searching
   * [Binary Search](https://github.com/TheAlgorithms/C/blob/master/searching/Binary_Search.c)