Combined immunohistochemistry and retrograde tracing was used to investigate the origin of the sensory calcitonin gene-related peptide (CGRP) innervation of the rat stomach. Up to 85% of spinal gastric afferents (T6-L1) contained CGRP immunoreactivity compared with less than 6% of vagal gastric afferents. By comparison substance P immunoreactivity occurred in about 50% of spinal gastric afferents and less than 2% of vagal afferents. The vagal afferents to the oesophagus were 14 and 26% substance P- and CGRP-immunoreactive respectively. The results suggest an important role for CGRP in gastric spinal afferents.