Mesoscale Convective Systems (MCS) frequently develop over the easternmost fringe of the tropical Pacific Ocean off the coast of Colombia and various regions of the country. Their genesis, dynamics and environmental conditions are not well known. We used information of Tropical Rainfall Measuring Mission (TRMM), Microwave Imager and Precipitation Radar (TMI and PR), to develop a quantitative classification of those MCS. Such classification made it possible to extract salient features related with mesoscale convection and its diurnal cycle during the 1998-2002 period. Results confirm that MCS represent about 70% of the total classified precipitation. Differences between rainfall over both the oceanic region and land-based rainfall over Colombia have been found in the seasonal and diurnal cycles. The diurnal cycle of rainfall over land exhibits an strong afternoon maximum, in contrast to the ocean region that’s an early morning maximum occurs over the study region. All of this results are according with related studies using both satellite and surface data.