diff --git a/allalgorithms/numeric/CheckFibonacci.py b/allalgorithms/numeric/CheckFibonacci.py
new file mode 100644
index 0000000..271071f
--- /dev/null
+++ b/allalgorithms/numeric/CheckFibonacci.py
@@ -0,0 +1,18 @@
+# -*- coding: UTF-8 -*-
+#
+# Check fibonacci number
+# The All ▲lgorithms library for python
+#
+# Contributed by: Natan Lucena
+# Github: @NatanLucena
+#
+
+import math 
+  
+def isPerfectSquare(x): 
+    s = int(math.sqrt(x)) 
+    return s*s == x 
+  
+def isFibonacci(n): 
+
+    return isPerfectSquare(5*n*n + 4) or isPerfectSquare(5*n*n - 4)