A survey of hospitalizations at the Chaim Sheba Medical Center, covering two nonconsecutive decades (1951-60 and 1970-79), included 213 patients (228 episodes) with infective endocarditis. The increase in the age of patients and in the frequency of atherosclerotic heart disease, as well as the introduction of techniques such as heart catheterization and open-heart surgery, are responsible for the differences in clinical course, microbiology and therapy. Despite the changed pattern, rheumatic heart disease remained the principal underlying disease in both periods and Streptococcus viridans remained the most common pathogen. Not a single case of drug addiction appeared in our material, despite its increasing frequency in Israel.