This report describes a 45-year-old man who developed acute bacterial endocarditis involving the aortic valve due to Klebsiella type 19. Consequent to the infection the patient developed aortic insufficiency and congestive heart failure. The patient failed to respond adequately to antibiotic therapy alone and rapid clinical deterioration required that the aortic valve be replaced despite the presence of active infection. Excision of the aortic valve appears to have removed the site of infection and replacement with a Starr prosthesis has corrected the aortic insufficiency. The patient has been followed for 15 months since the operative procedure, during which time he has returned to his work as a bricklayer. The encouraging result obtained in this patient suggests that in selected instances, valve excision and replacement under antibiotic coverage provide a possible therapeutic approach to certain difficult cases of active bacterial endocarditis.