The clinical profile of acute rheumatic fever below the age of five years was studied prospectively in 53 children seen over a period of seven years. The majority presented with pain in the joints, manifested as arthritis in 81% and arthralgia in 15%. Four per cent presented with congestive heart failure. Carditis developed in 42%, with a high incidence of pericarditis (6%) and congestive heart failure (15%) and a mortality of 2%. The incidence of Erythema marginatum was 2%, while chorea and subcutaneous nodules were not seen. Data from this prospective study, when compared with those of other prospective studies of acute rheumatic fever throughout childhood, clearly show a similar incidence of arthritis and carditis with a slightly more aggressive nature of carditis in children under five years. These findings are in marked contrast to recent reports describing the clinical profile of acute rheumatic fever in this age group.