The climatic information (rainfall and temperature) generated by the ECHAM4 General Circulation Model (GCM) under A2 and B2 scenarios of the IPCC was used as the input to the PRECIS Regional Climate Model (RCM) to downscale the output at approximately 50 km resolution covering Sri Lanka. The simulations were performed for the baseline period of 1961-1990 and three future periods of 2010-2039 (2020s), 2040-2069 (2050s) and 2070-2099 (2080s). The projected changes in mean annual temperature and rainfall have been calculated for all the three future time slices with respect to the base line climate. This study reveals that average annual temperature of Sri Lanka will increase with a 2.5-4.5°C range by the year 2080 under the A2 scenario with a possible average annual temperature increase of 2.5-3.25°C under the B2 scenario. Both these projections are analogous with the IPCC global projections of temperature changes at the turn of the century. In terms of future rainfall climatology of Sri Lanka, projections with A2 scenario reveal that Dry zone will become more drier while the Wet and Intermediate zones to become more wetter than at present as we reach the end of century. Meanwhile, B2 scenario uncovers a relatively complex situation of both Dry zone and Central highlands of Sri Lanka to become drier than today as time progresses while the wetter parts of Sri Lanka to become further wet, but at a lesser rate compared to the A2 scenario.