We report the pyroelectric response of c-axis oriented, undoped, wurtzite, aluminum nitride reactively sputtered onto polished silicon wafers. The voltage between a metallic contact on the AlN surface and the n(+)-doped silicon substrate was monitored during pulsed infrared, radiant heating. From analysis of the data, a pyroelectric voltage coefficient, P-V, in excess of 0.5 x 10(6) V/ m/K was extracted for films in the 600 to 2500 angstrom thickness range. (C) 2005 The Electrochemical Society.