Coral reef areas are globally important as ecosystems for their role in the geochemical mass balance of the ocean as well as providing habitats for many important marine organisms (Smith 1978). The basis of the reef system is the hermatypic (reef-building) corals, and the health of these important organisms can be affected by both natural and man-induced stress (Johannes 1978). Coral reefs often lie close to tanker routes as well as areas of off-shore production and oil refining (Loya 1976). Therefore the effect of oil on coral has been a subject of much interest (Loya & Rinkevich 1980). Our studies of the effect of oil pollution on coral in Bermuda led us to investigate the uptake and depuration of petroleum hydrocarbons by coral reef colonies. There have been few previous studies on the uptake and release of petroleum hydrocarbons by coral, and the analytical techniques used sacrifice the whole coral at the time of sampling (Meyers et al. 1974; Peters et al. 1981). We modified a well-known method using (9-14C) phenanthrene (Solbakken et al. 1979) and measured the uptake and followed the depuration of this labeled aromatic hydrocarbon in individual coral colonies. The aim, therefore was to use the radiolabeled compound to investigate the extent of uptake and depuration and investigate the relationship between coral tissue and mucus in these processes.