In this note, we find a monomial basis of the cyclotomic Hecke algebra H r, p,n of G(r, p, n) and show that the Ariki-Koike algebra H r,n is a free module over H r, p,n , using the Gröbner-Shirshov basis theory. For each irreducible representation of H r, p,n , we give a polynomial basis consisting of linear combinations of the monomials corresponding to cozy tableaux of a given shape.