In patients suffering from infective endocarditis (IE), initial symptoms and clinical findings are unspecific. Physicians primarily involved should always consider IE a potential diagnosis. Any delay in diagnosis and thus in an adequate antimicrobial therapy has a significant negative prognostic influence. Any subject suspected to have IE should immediately have a transthoracic echocardiography (TTE) by an experienced examiner. If the TTE results are inconclusive, transesophageal echocardiography (TEE) has to be performed without delay. Other steps in diagnosis, medical and surgical therapy follow established and evidenced-based guidelines. Antimicrobial regimens are standardized for IE, for which demonstration of causative microorganisms from blood cultures or other microbiological sources is unavoidable. If there are problems in diagnosis, if difficult-to-treat microoganisms are isolated or difficult-to-treat situations complicate active IE, a reference center should be involved.