The Cambay Basin in the NW part of the Indian Peninsula is a commercial petroleum producer from Tertiary sediments resting on the basic lava flows known as Deccan Traps. Cretaceous sediments which underlie the Deccan Traps are exposed in the eastern and western margins of the basin and are also encountered in the subsurface. The paleogeographic reconstruction of the Cambay Basin suggests that the northern part, possessing a thin cover of Cretaceous sediments, has meagre petroleum prospects. However, the southern part of the basin, where more than 1,000 m of Cretaceous sediments were deposited by two independent drainage systems, may be more lucrative. Suitable facies for generation and accumulation of petroleum are expected in this part of the basin.