As the number of recreational athletes performing exercise and participating in competitions at a high-level increases, exercise-induced cardiac symptoms may become a more common problem, not least because recreational athletes often continue high-level exercise programs into advanced ages. We investigated the prevalence of cardiac symptoms and diagnoses among 201 athletes referred for cardiac evaluation at a Sports Cardiology Clinic in Denmark. To our knowledge, this is the first systematic study of athletes referred for suspected cardiac disease. The athletes were all well-trained recreational to elite athletes who participated in various sports with different training loads and a wide age span (13-66 years). All patients were referred by physicians, primarily their general practitioner (38%), and palpitations were the most common cardiac symptom (40%). Cardiac symptoms had a sensitivity of 86% in detecting cardiac disease and a specificity of 13%. Cardiac disease was diagnosed in 44% of the patients, and atrial fibrillation was the most prevalent diagnosis (7.5%). Cardiac diseases with therapeutic- or sports-related consequences for the patients were diagnosed in 28% of the population, but only 1% received a recommendation to avoid high-level sports indefinitely.