diff --git a/ft_strlen.s b/ft_strlen.s
new file mode 100644
index 0000000..f87f27c
--- /dev/null
+++ b/ft_strlen.s
@@ -0,0 +1,11 @@
+global ft_strlen
+
+ft_strlen:
+	xor rax, rax
+.loop:
+	cmp byte [rdi + rax], 0
+	je .done
+	inc rax
+	jmp .loop
+.done:
+	ret