We compared the in vitro activity of daptomycin, a new lipopeptide antibiotic, with that of vancomycin and other selected agents against 95 coagulase negative staphylococci (CNS) isolates causing septicemia or foreign-body infections in immunocompromised patients. These strains were classified as follows: 51 methicillin-susceptible CNS (23 slime producers); 44 methicillin-resistant CNS (23 slime producers). We also investigated the activity of daptomycin against 50 Enterococcus faecalis isolates. Minimal inhibitory concentrations (MICs) were determined by the broth microdilution method. Daptomycin at a concentration of 2 mg/L was inhibitory for all the evaluated strains. Vancomycin and ciprofloxacin showed good activity: 90% of the strains were inhibited by these agents at 8 mg/L. The activity of netilmicin, rifampin and trimethoprim-sulfamethoxazole was instead limited. Resistance to the antimicrobial agents tested was seen with increased frequency among slime producing strains. Daptomycin and teicoplanin were the most active agents tested against E. faecalis (MIC90 0.25 mg/L and 0.12 mg/L).