This work examines the effects of clouds on backscattered ultraviolet radiation via analysis of satellite observations and radiative transfer modeling. Measurements from the continuous scan mode of the Nimbus 7 SBUV instrument show that the enhancement in backscatter albedo associated with clouds generally increases with wavelength. However, high clouds enhance the backscattered ultraviolet radiation at short wavelengths more than do low or middle level clouds. For an overhead Sun in the tropics, the enhancements in backscattered radiance from high clouds are about 5 times those from low clouds at a wavelength of 300 nm. For a typical mid-latitude atmosphere with a solar zenith angle of 60¿, the enhancements in backscattered radiance from high clouds are approximately double those due to low level clouds. ¿ American Geophysical Union 1995