The experiences in a series of 65 patients with liver abscesses seen at the University of Cincinnati Medical Center have been reviewed and studied to obtain a better understanding of the incidence, etiology, pathogenesis, diagnostic problems, effectiveness of therapy, morbidity, and mortality of this serious disease. This study has emphasized the fact that this disease is life-threatening and that the mortality of undiagnosed and undrained cases was 100%. In contrast, there was no mortality in all of the cases but one in which a diagnosis had been made and surgical drainage was instituted. During the past five years, our ability to diagnose and localize liver abscesses 2 cm or larger has been greatly enhanced by the use of radioactive isotope liver scanning techniques, aided more recently by hepatic arteriography. The benefits of these new techniques have been evident not only in a marked reduction in mortality but also in a greatly increased number of correctly diagnosed cases for which successful operations could be done.