Cyclic AMP (cAMP) has been postulated to regulate many of the events in the development of the eukaryotic social ameba Dictyostelium discoideum. The various suggested roles of cAMP could be tested were it possible to reversibly elevate cAMP levels in the organism. To this end we examined the effect of forskolin, which activates the adenylate cyclase of many eukaryotic organisms. We found, however, that the drug does not elevate cAMP levels in intact D. discoideum. In addition, it does not stimulate the adenylate cyclase in either its basal state or activated state.