The inhibitory neurotransmitter gamma-aminobutyric acid (GABA) has been implicated in the pathophysiology of depression. Therefore, we examined cerebrospinal fluid (CSF) levels of GABA in depressed patients (N = 25) and normal controls (N = 20). There was no significant difference between the groups. However, among the depressed patients the subgroup of unipolar melancholic patients (N = 13) had significantly lower CSF levels of GABA than the rest of the depressed patients (N = 12). There was no significant difference for CSF levels of GABA between depressed patients who were (N = 14) or were not (N = 11) cortisol non-suppressors. It was of interest that among the controls there was a significant negative correlation between CSF levels of GABA and CSF levels of norepinephrine.