The bacteria most frequently isolated from blood cultures of haematology patients in Warsaw were staphylococci (58.0%), Enterobacteriaceae (18.6%), non-fermenting rods (6.9%), enterococci (4.3%) and anaerobes (4.3%). Coagulase-negative staphylococci were the most common species isolated (92.7%) with 83.2% of these strains resistant to methicillin. Among enteric bacteria, 17.3% strains produced extended-spectrum-beta-lactamases. All eight isolates of enterococci showed high level resistance to aminoglycosides.