Enterococci are increasing in importance as nosocomial pathogens and causes of severe sepsis in immunocompromised patients. From September to November 1989, a survey of 898 enterococcal isolates showed that 52 had acquired high-level resistance to penicillin and ampicillin (MIC greater than 100 mg/l). These were all Enterococcus faecium, did not produce beta-lactamase and showed high-level resistance to gentamicin and streptomycin as well. The majority were urinary isolates, but a few caused bacteraemia in severely ill patients. The potential spread of these highly-resistant enterococci would limit the therapeutic options for systemic infections.