A transient CO2 experiment has been performed with the BMRC coupled atmosphere ocean General Circulation Model (GCM). No flux corrections were used in the experiment. A roughly linear temporal increase in global surface temperature is found in response to the CO2 increase. The rate of increase is consistent with the (relatively low) equilibrium response found previously using the Atmospheric GCM and a simple ocean. Ocean surface temperatures increase more at mid latitudes than at high northern or southern latitudes where heat is sequestered into the deep ocean. Despite the secular climate drift which occurs in the model, the major patterns of atmospheric and oceanic temperature change are similar to changes noted elsewhere (from flux corrected models). This adds further support to the main conclusions drawn from transient CO2 experiments performed elsewhere with coupled GCMs. ¿ American Geophysical Union 1995