Autopsy incidence of infective endocarditis during the past 50 years was analysed to review the changes in the clinico-pathologic pattern if any. 185 cases were recorded in a total of 39931 autopsies giving an average incidence of 0.46%. The cases were classified into groups I, II & III depending upon whether the endocarditis super-vened on normal hearts, diseased hearts or followed surgery, re-spectively. The fifty year period could be divided into three phases on incidence. First phase (1927-41) represented pre-antibiotic era in which group I cases predominated and causative organisms in 801" o f cases were virulent cocci such as staphylococci, haemolytic streptococci and pneumococci. In the second phase (1948-66) the general incidence was reduced by 50%. Group II cases predominat-ed and the most common etiologic agent was streptococcus viridans (40%). In the third phase (1967-76) the general incidence has reached again to preantibiotic level with coagulase positive staphy-lococci, Gram negative bacilli and fungi accounting for 90% of cases. Group III contributed significantly in this phase. The changes in incidence are primarily due to fall and rise in Group I cases. Incidence of rheumatic heart disease with endocar-ditis which mainly forms Group II is declining steadily in post-antibiotic era. There is no shift in the peak age incidence which remains in the 3rd decade. Males with rheumatic heart disease are more prone to infective endocarditis than similarly affected females. There was no change in frequency of involvement of various valves or sites of embolization