We describe a syndrome of spontaneous orofacial dyskinesias and cage stereotypies in a singly housed adult cynomolgus monkey never previously exposed to neuroleptic drugs. Abnormal movements were readily suppressed by acute treatment with haloperidol (0.03–0.24 mg/kg i.m.) or SCH23390 (0.05–0.2 mg/kg i.m.) but not by physostigmine (0.005–0.04 mg/kg i.m.) or scopolamine (0.0025–0.04 mg/kg i.m.). The symptomatology and response to pharmacological manipulations was indistinguishable from that previously attributed to chronic neuroleptic treatment in primates. Our findings indicate that neuroleptic-induced tardive dyskinesias in most primate studies have not been clearly demonstrated.