We wished to assess general practitioners' and psychiatrists' sensitivity and specificity in the diagnosis of depression, rationale for drug of choice, average and range of prescribed daily doses of antidepressants, and use of therapeutic drug monitoring (TDM). A questionnaire survey was given to 264 psychiatrists and general practitioners (GPs) in one urban area of Stockholm and the rural county of Jamtland, Sweden. The response rate was 86% (n = 228). The survey was validated against independent studies of actual prescription rates. One of eight physicians presented with a hypothetical case history of major depression appeared unwilling to use antidepressants. Two-thirds of the GPs and one-fourth of the psychiatrists usually prescribed doses that were too low. Many doctors never prescribed doses higher than 150 mg/day of common tricyclic antidepressants, although many patients clearly need higher doses. The choice of drug was based mostly on the therapeutic tradition and seldom on considerations of scientific evidence. The few physicians who utilized TDM (plasma concentrations) for dosing prescribed a more flexible dosage schedule and higher average doses as well as higher maximal doses. Interestingly, there were no significant differences in dosing between GPs and psychiatrists in this group, while striking differences were found in the whole study group, with GPs prescribing much smaller doses. Regular use of TDM as a means for individualizing the dose regimen of antidepressants should be encouraged, as well as continuous education of general practitioners in the diagnosis and treatment of depression.