We introduce the notion of $M$-BCK/BCI-algebras and $M$-fuzzy subalgebras for a set $M$, and investigate some of their properties. We establish $M$-fuzzy subalgebras from old one. We give characrerizations of $M$-fuzzy subalgebras. We show that the $M$-homomorphic image and inverse image of an $M$-fuzzy subalgebra is also an $M$-fuzzy subalgebra.