Some Aerococcus-like organisms (ALOs) have recently been described in Denmark. The bacteria were originally isolated from the urine of elderly patients with urinary tract infections. Since 1987, we have identified 17 cases of bacteremia/septicemia in which ALOs have been isolated in pure culture of blood; we report the data from these cases. Six of the patients presented with endocarditis, eight presented with urosepticemia, and three presented with septicemia. In all but one of the reports, the urinary tract was suspected as the focus of infection, and ALOs were isolated from the urine of nine patients. All but one patient had predisposing illnesses; these were predominantly of urinary or cardiac origin. Five patients died of their infection, two survived the infection but eventually died during hospitalization, and 10 recovered. All of the patients received adequate antimicrobial therapy.