Buspirone is known to stimulate prolactin release. Clinical studies (e.g. in chronic fatigue syndrome) suggest that the response may be influenced by baseline cortisol levels. We conducted a double-blind placebo-controlled study to examine the relationship between the prolactin response to buspirone challenge and baseline cortisol level. Fifty healthy volunteers took part in the study. Buspirone was found to consistently elevate PRL levels above those seen following placebo administration. The PRL response as measured by area under the curve was highly correlated with the baseline cortisol level.