diff --git a/C/Euler_totient_Function.c b/C/Euler_totient_Function.c
new file mode 100644
index 0000000..b6193ab
--- /dev/null
+++ b/C/Euler_totient_Function.c
@@ -0,0 +1,29 @@
+//C program to calculate Euler's Totient Function
+#include <stdio.h>
+
+// Function to return gcd of a and b
+int gcd(int a, int b)
+{
+    if (a == 0)
+        return b;
+    return gcd(b % a, a);
+}
+
+// A simple method to evaluate Euler Totient Function
+int phi(unsigned int n)
+{
+    unsigned int result = 1;
+    for (int i = 2; i < n; i++)
+        if (gcd(i, n) == 1)
+            result++;
+    return result;
+}
+
+// Driver program to test above function
+int main()
+{
+    int n;
+    for (n = 1; n <= 10; n++)
+        printf("phi(%d) = %d\n", n, phi(n));
+    return 0;
+}
\ No newline at end of file