Abstract | In commutative algebra, E. Miller and B. Sturmfels defined the notion of multidegree for multigraded modules over a multigraded polynomial ring. We apply this theory to bifiltered modules over the Weyl algebra D . The bifiltration is a combination of the standard filtration by the order of differential operators and of the so-called V -filtration along a coordinate subvariety of the ambient space defined by M. Kashiwara. The multidegree we define provides a new invariant for D -modules. We investigate its relation with the L -characteristic cycles considered by Y. Laurent. We give examples from the theory of A -hypergeometric systems M A ( β ) defined by I.M. Gelfand, M.M. Kapranov and A.V. Zelevinsky. We consider the V -filtration along the origin. When the toric projective variety defined from the matrix A is Cohen–Macaulay, we have an explicit formula for the multidegree of M A ( β ) . |