Two hundred fifty five medial prefrontal cortical (MPFC) and 187 caudate-putamen (CPu) sites were evaluated for intracranial self-stimulation in 67 animals using moveable electrodes and collecting trade-off functions between current and frequency. Eleven percent of the examined areas, located predominantly in the ventromedial aspects of MPFC and CPu, showed reliable self-stimulation and the average charge of 1.12 and 1.11 muC respectively, values that are in line with those reported for the Medial forebrain bundle. The distribution of charge, however, was greater than reported for the latter region, and ranged between 0.68 to 1.63 muC across sites. Some subjects were implanted with two electrodes, one aimed at the MPFC, and the other at the CPu, ventral tegmental area, or lateral hypothalamus. Only animals with CPu placements showed transference of self-stimulation to the MPFC, suggesting that these two regions might form part of the same reward substrate, a view that has anatomical, electrophysiological and recently behavioral support.