The white abalone Haliotis sorenseni occupied rocky reefs in high densities around the California Channel Islands at depths of 26–65 m in the early 1970s. By 1981, white abalone densities had declined two orders of magnitude, and the species had virtually disappeared by the early 1990s. From April 1992 through December 1993, we searched 30,600 m2 of suitable habitat at 15 locations known previously to support the white abalone. We found three live individuals (mean density, 0.0002/m2; SE, 0.0005). All three were near the maximum size common for the white abalone. At average densities, an equivalent search in the 1970s would have revealed 6,120–30,600 adults. Fishery landings reflected this population collapse. Annual commercial landings averaged 41 metric tons in 1971–1976, peaked abruptly at 65 tons in 1972, then plummeted to 0.140 ton in 1981; landings averaged only 0.153 ton from 1991 through 1994. Recreational landings, never numerous, virtually ceased after 1983. During the 1992–1993 survey, we also found 119 empty white abalone shells, 42–195 mm long, at a mean density of 0.0085/m2 (SE = 0.0065). The last major white abalone recruitment event at the California Channel Islands was apparently in the late 1960s. Survivors of legal harvest in the 1970s were so few and so sparsely distributed that no significant reproduction has occurred since then. The California white abalone population appears to have collapsed in the 1970s and is approaching extinction from natural causes some 20 years after intense exploitation ended.