Aortic valve lesions are often found in patients with rheumatic diseases, but their clinical significance has not been properly evaluated. In the present study, the echocardiographic files of the cardiology unit of the Oulu University Hospital were screened for a diagnosis of aortic insufficiency (AI). The aetiology of the valve disease and specific details of the rheumatic disease were evaluated in 160 patients. Twenty-eight patients (18%) had a history of rheumatic fever. Rheumatic disease was found in 14 patients (8.8%) with AI, which is significantly more than the prevalence of rheumatic diseases (1.8%) in the corresponding age group (35-100 years) in Finland. Rheumatoid arthritis or juvenile rheumatoid arthritis was found in seven patients (4.4%), whereas ankylosing spondylitis or seronegative spondylarthropathy were found in four patients (2.5%). Other rheumatic diseases included Takayasu's arteritis (two patients) and scleroderma (one patient). When 38 patients with pure AI without other possible aetiology were analysed, rheumatic disease was found in five patients (13%). Patients with rheumatic disease as a potential aetiology of AI often had symptomatic valve disease, which required surgical treatment, although great differences between different aetiologies were not found.