Nanosecond (ns) photoelectric effects have been observed in all-oxide p-n junctions of La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 for the first time. The rise time was about 23 ns and the full width at half maximum was about 125 ns for the open-circuit photovoltaic pulse when the La0.9Sr0.1MnO3 thin film in the p-n junction was irradiated by a laser of ~20 ns pulse duration and 308 nm wavelength. The photovoltaic sensitivity was 80 mV/mJ for a 308 nm laser pulse.