The GPI technique is a simple method which was developed to estimate convective rainfall in the tropics over large regions and climatological time scales. The technique uses equivalent blackbody temperatures of the tops of clouds at resolution of a single pixel as the sole parameter to estimate rainfall. Since the tropics are uniformly warm relative to the tops of convective clouds, cloud-top temperature alone can be used to estimate the rainfall from convective system, and in portions of the extra-tropics during the warm season In this study, the rainfalls occurred over Samsun Region within April and May 1996 have been determined by means of meteorological stations and METEOSAT-5 satellite data. The GPI method was applied so as to cover the complete region of Samsun. It has been studied to determine the best satellite rainfall estimation model for the region. As a result of this study, it was found that the GPI method overestimates the rainfall over Samsun. Results were discussed in detail.