Acoustic shadowing by an isolated seamount has been studied by examining the multipath propagation measurements obtained in a shot run that passed over the seamount peak. Source depths of 24 and 196 m were used in the experiment. In the acoustic shadow, the propagation loss for the shallow 24‐m shots increased by 10–15 dB over the loss expected in the absence of the seamount. Examination of the pressure‐time history for shots deployed in the shadowing region revealed that the signals consisted of two components. The first and dominant pulse was determined to be a diffracted wave which passed over the seamount by rough‐surface forward scattering and diffraction. The subsequent group of weaker pulses was attributed to the energy which had passed over the seamount by a series of surface–bottom interactions. The shadowing loss increased by 3 dB per octave for frequencies greater than 50 Hz, in agreement with theory, but is appreciably greater than the predicted values at lower frequencies. The shadowing loss for the 196‐m shots was about 5 dB less than that observed for the shallower shots.