SUMMARYLet u and v be, respectively, the solutions to the Cauchy problems for the dissipative wave equationand the heat equationWe show that, as t → +∞, the norms 9 k t D x u(· ; t) L 1 (R n ) and 9 k t D x v(· ; t) L 1 (R n ) decay to 0 with the same polynomial rate. This result, which is well known for decay rates in L p (R n ) with 26p6 + ∞, provides another illustration of the asymptotically parabolic nature of the hyperbolic equation (1).