All bloodstream strains, total 1463, isolated during a 1 month period in 105 hospitals representing all geographical areas in France were collected to study their antimicrobial susceptibility. The three major species were Escherichia coli, Staphylococcus aureus and coagulase-negative staphylococci. Among the 242 S. aureus, 87 were resistant to methicillin and among those 99% were resistant to ciprofloxacin, 11.5% to gentamicin, 1% to quinupristin/dalfopristin and 8% were heterogeneously resistant to vancomycin. Study of the methicillin-resistant S. aureus indicated that 12 clones had disseminated in French hospitals, six being heterogeneously resistant to vancomycin. Among the Streptococcus pneumoniae, 43% showed decreased susceptibility to the penicillins and 42% to erythromycin. One isolate was highly resistant to fluoroquinolones. Gentamicin, cefotaxime, ciprofloxacin and gatifloxacin resistance was rare in Enterobacteriaceae with 95% of strains susceptible. The incidence of extended-spectrum beta-lactamases was quite low. Moreover more than 25% of Pseudomonas aeruginosa strains were resistant to ciprofloxacin and gentamicin. The magnitude of antibiotic resistance in bloodstream isolates, in particular Gram-positive bacteria, emphasizes the importance of hospital control measures, rational prescribing policies and new vaccine strategies.