The objective of the study was to compare the frequency of mental disorders in cardiology outpatients to the number of patients with psychological problems identified by cardiologists. In a cardiology outpatient service, 103 consecutive patients were asked to participate in the study. Of these 86 were included and screened for mental disorder with the Primary Care Evaluation of Mental Disorders (PRIME-MD), Structured Clinical Interview for DSM-IV (SCID) psychosis screening, the Clock Drawing Test, and the WHO-5 Well-being Index. The cardiologists were asked to rate the severity of somatic and mental problems in each patient on visual analogue scales (VAS-som and VAS-men). The current treatments, including psychiatric and psychological treatments, were noted, and the survival was followed for 3 years. Of the 86 patients included, 34 (40%) had a diagnosis of mental disorder. Eleven (12.8%) had major depression, six (7.0%) minor depression, six (7.0%) anxiety disorder, two unspecified somatoform disorder, seven (8.1%) dementia, one alcohol abuse and one psychosis. Three of the patients were in long-term psychopharmacological treatment. Although the cardiologists predicted mental disorder significantly better than chance, none of the patients was in relevant treatment for their mental disorder. At 3-year follow-up, 20 (24%) of the patients had died. Age and severity of heart disease predicted mortality, while the presence of a mental disorder did not. Mental disorders, especially depression, were frequent in cardiology outpatients. Even in cases where the cardiologists identified psychological problems, the diagnosis had no consequence, as none of the patients was offered relevant treatment.