Coral reef sites studied and photographed in the Gulf of San Blas on the Caribbean coast of Panama in 1970-71 were revisited in 1991. There was a dramatic decline in the most common foliose and branching corals and an increase in algal cover. Agaricia spp. which formed most of the patch reefs and lined the slopes of channels and deep bays were mostly dead or being outcompeted by the brown alga Lobophora. Extensive, shallow Porites porites mounds had been harvested for fill by the Kuna. Deeper mounds were overgrown 50-100% by algae. Only debris fields and scattered small colonies remained of once extensive thickets of Acropora cervicornis and, in higher wave energy areas, A. palmata was mostly dead. In contrast, massive corals appeared generally healthy. These results emphasize the sensitivity of coral reefs to global change and the need for long-term comparative research.