There have been several reports of non-detection and undertreatment of major depression during the past decades. In this study, we investigated how accurately major depression was assessed, diagnosed and treated according to gold standards, and whether any trend could be found from 1989 to 2001 in Finland. In total, documents of 4447 patients were retrospectively checked at most four times to find the patients fulfilling the study criteria. Finally, 531 patients were included in the study. The major finding of the study was the improved diagnostic assessment of patients with major depression seen in psychiatric settings. However, a systematic and comprehensive approach in asking about and recording subtyping, severity and comorbidity of depression was insufficient. Another major finding of the study was the improved pharmacotherapy of patients with major depression. It seems to be relevant that problems in the quality of care for depression in psychiatric settings are now more likely to be related to suboptimal intensity and monitoring of treatment than to mere lack of treatment.