Fifty-eight new K-Ar age determinations from Tahiti and Moorea indicate that these islands were volcanically active during the past 2 m.y. The ages from Tahiti are clearly younger than the more westward island, Moorea. This age pattern, along with existing data for other Society Islands, demonstrates a migration of volcanism from northwest to southeast for this island chain. The alignment and progression of volcanism for the Society Islands are consistent with the suggested movement of the Pacific plate over a hot spot; however, the rates of rotation implied by age data for the Society Islands and other Pacific island chains are greater than rates indicated by other estimates. This discrepancy may result from hot-spot movement in a direction opposite to the plate motion.