We present evidence for an ancient and voluminous subaerial landslide of the southern flank of Tahiti, Society Islands. During a marine geophysical survey in 1996, submarine mass wasting deposits were mapped as far as 60 km from the southern shore of the island. Acoustic imagery reveals a surface of 2950 km2 of debris avalanche and hummocky terrain. Based on bathymetric data, the volume of the debris is estimated to be 1150 km3. In comparison with Hawaiian and other oceanic island landslides, it can be classified as a giant, rapid and cataclysmic event. Tahiti morphology and the distribution of volcanic ages over the island strongly suggest that the slope failure initiated near the top of the southern island flank, between 650 and 850 ka. The landslide scar was subsequently filled by eruptions. The estimated volume of the subaerial removed material exhibits a large discrepancy with the volume of the submarine deposits that can be explained by recurrent slide events. ¿ 2001 American Geophysical Union