The effect of shadows cast by vertical protrusions on AVHRR data has been investigated. The AVHRR channel-1 data from the same ground area imaged from various viewing angles are examined. These data were obtained from nine orbits during eight successive days. The atmospheric effects were removed and an analysis of the resulting surface-leaving radiance shows that the effect of shadows is an important factor contributing to off-nadir viewing effect on the remotely sensed data.