diff --git a/ft_isdigit.c b/ft_isdigit.c
new file mode 100644
index 0000000..e74b707
--- /dev/null
+++ b/ft_isdigit.c
@@ -0,0 +1,8 @@
+#include "libft.h"
+
+int	ft_isdigit(int c)
+{
+	if ((c >= '0' && c <= '9'))
+		return (1);
+	return (0);
+}
diff --git a/libft.h b/libft.h
index 697b3f3..16f43aa 100644
--- a/libft.h
+++ b/libft.h
@@ -1 +1,2 @@
-int ft_isalpha(const char c);
+int	ft_isalpha(const char c);
+int	ft_isdigit(int c);