Geophysical investigations to determine the most probable sites for hydrocarbon prospects in lower Sokoto Basin was carried out using the total magnetic field values that were obtained by digitizing the contour maps of the basin, which was used to produce the composite map of the area. The lower Sokoto Basin is situated between latitudes 10o.50″ N to 11o .50″ N and longitude 4o″ E to 5o″E. Spectral depth analysis were carried out on the residual magnetic map to study the subsurface geological features of the basin. The results of the spectral studies indicate an increase in sedimentation southwards with several depressions on the basement rock. Two prominent magnetization layers of depths varying from 0.589 km to 1.249 km and 2.506 km to 3.174 km were observed. The highest sedimentary thickness of 3.2 km encountered using spectral depth analysis is in the vicinities of Konkoso (sheet no: 117). These areas, where higher sedimentary thicknesses are encountered in this study, are the most probable sites for prospect of hydrocarbon accumulation in the area.