Guwahati is fast emerging as a multi-ethnic cosmopolitan city with a burgeoning population and rapid unplanned urbanization. The city is located in the lower Brahmaputra Valley and underlain by thick alluvial deposits ranging from 25 to 600 m with granitic exposure at places. Large earthquakes in the past caused widespread damage to life and property in this terrain. Hence the study of seismicity of this area is mandatory for the purpose of seismic hazard analysis. This study attempts to evaluate probabilistic seismic hazard parameters'b'value, the mean return period and the maximum regional magnitude. The seismic hazard parameters have been calculated using Gutenberg-Richer (GR) recurrence relation and Kijko method for the study region. Higher'b'value obtained in this study features the geological heterogeneity and increased seismcity of Guwahati region.