Oxytocin-like immunoreactivity (IR-OXT) was detected in extracts of human spinal L5 and Gasserian ganglia by a radioimmunoassay (RIA) specific to oxytocin (OXT) and was identified by high-performance liquid chromatography (HPLC). One of the two immunoreactive peaks obtained on HPLC was found to elute at the same position as the OXT standard. The results reveal the presence of chromatographically identified OXT immunoreactivity in human sensory ganglia.