To examine metabolic changes in the left basal ganglia in chronic schizophrenia, we performed proton magnetic resonance spectroscopy (1H-MRS) in 21 medicated schizophrenic patients and 21 gender and age-matched normal controls. Compared to the normal subjects, the schizophrenic patients showed a significantly increased level of choline containing compounds (Cho) (t = 2.60, p < 0.05) and ratio of Cho to N-acetylaspartate (NAA) (t = 2.46, p < 0.05) in the left basal ganglia. No significant correlation was observed between the 1H-MRS measurements in the left basal ganglia and clinical symptom scores as evaluated using the Brief Psychiatric Rating Scale (BPRS). The chlorpromazine equivalent neuroleptic dosage was positively correlated with the level of NAA (r = 0.38, p < 0.05) and negatively correlated with the Cho/NAA ratio (r = -0.34, p < 0.05). These findings suggest that these changes in metabolites in the left basal ganglia may reflect some of the functional and morphological abnormalities reported previously for the brain in schizophrenia.