We report five cases of Cushing's disease where the patients were given a therapeutic trial of cabergoline. Morning serum cortisol, adrenocorticotrophic hormone (ACTH), and sleeping cortisol concentrations were significantly raised. Magnetic resonance imaging (MRI) scans revealed pituitary microadenomas in 3 patients but were normal in the others. Ectopic ACTH production was excluded in the 2 patients with normal MRI scans. All were given a therapeutic trial of cabergoline (1 mg daily). Four patients responded with a prompt fall in serum cortisol levels and had a sustained clinical and biochemical remission for 378, 44, 28 and 14 days, respectively. One patient failed to respond. In conclusion, we suggest that all patients with Cushing's disease should undergo a therapeutic trial of cabergoline. Responders can then be prepared for surgery or, if needed, treated medically in the long term.