BACKGROUND. The 'defeat depression' campaign emphasizes the importance of adequate prescribing of antidepressants in general practice. AIM. A study was undertaken to investigate the prescribing habits of a group of general practitioners and psychiatrists. METHOD. A postal questionnaire was sent to 123 general practitioners and 97 psychiatrists in south Wales. RESULTS. The response rate among general practitioners was 60% and among psychiatrists it was 67%. As a group, the psychiatrists reported using significantly higher daily dosages of antidepressant medication for adult and for elderly patients over a longer period compared with general practitioners. Fifty two per cent of 68 general practitioners and 17% of 60 psychiatrists reported using lower than recommended daily treatment dosages for adult patients and 40% of 68 general practitioners and 7% of 62 psychiatrists used a shorter than recommended period of continuation therapy (less than four months). Both groups showed a wide variation in the use of maintenance therapy. CONCLUSION. Educational efforts should be made to improve the prescribing habits of general practitioners and psychiatrists.