This review on infective endocarditis (IE) is based on clinical studies carried out in Göteborg since 1984, data obtained from a Swedish national registry of IE since 1995 and existing literature. IE is still a great challenge in medicine, although improved bacteriological and echocardiographical techniques have facilitated diagnosis. In Sweden the incidence of IE is about 6 per 100,000 inhabitants a year. During recent decades IE has changed character. Patients are older, fever is often the only major symptom and a new murmur is less frequent. Streptococci, including viridans species and staphylococci, are still the most common bacteria found. Antibiotic treatment for 4-6 weeks may reduce mortality of IE to 30-50%. For further reduction, heart surgery is necessary in 20-25% of patients in order to remove infected tissues and restore valve function. Rapid diagnosis, careful antibiotic treatment and optimal surgery may reduce mortality associated with treatment to 10%. Antibiotic treatment is still mainly empiric. Penicillin and aminoglycoside for 2 weeks only seem to be effective in uncomplicated IE caused by alpha-streptococci. Otherwise, 4 weeks of treatment is needed, but aminoglycoside treatment may be reduced to 1 week in general and 2 weeks for enterococcal infections.