Ultrafast photoelectric effects have been observed in p-n heterojunctions of La0. 7Sr0.3MnO3(LSMO)/Si and LSMO/SrTiO3-/Si for the first time. The rise time was about 1 ns and the full width at half maximum was about 2 ns for the photovoltaic pulse when the hetero junction was irradiated by a laser of ～25 ps pulse duration and 1064nm wavelength. The photovoltaic sensitivity was as large as 435 m V/mJ for a 1064nm laser pulse. No such pulse was observed with irradiation from a pulsed 10.6μm CO2 laser.