The basal ganglia of rhesus and squirrel monkeys were examined using immunohistochemical techniques with antibodies against the neurotensin-related hexapeptides Lys8-Asn9-Neurotensin(8-13) (LANT6) and Neuromedin N. A high percentage of neurons in both segments of globus pallidus and many large neurons of the striatum were found to label for LANT6, but not Neuromedin N. Previous studies have shown that LANT6 or a LANT6-like substance is present in many pallidal neurons in a wide range of vertebrate species. The current results indicate that a LANT6-like substance that is distinct from Neuromedin N is also present in many pallidal neurons in primates. This raises the possibility that this substance may be involved in neurotransmission between the pallidum and its projection targets.