Sixty radiocarbon measurements were performed on aragonite from annually banded corals collected from three sites in the Galapagos Islands. Preanthropogenic D14C values of coral that grew around A.D. 1930 averaged -70%0. This is substantially lower than average values previously reported (-51%0) for corals from Florida and Belize in the western North Atlantic Ocean. A decrease of 6% was noticed in coral that grew from 1930 to 1954. This decrease could be interpreted as a Suess effect in surface ocean water. The 100%0 increase in D14C for coral that grew from 1954 to 1973 is the result of bomb-produced 14C that was introduced to the surface ocean waters. The 14C levels in corals that grew during El Ni¿o years were considerably higher than those for normal years. These higher values are attributed to the absence of upwelling at the equator during El Ni¿o events.