Gemifloxacin (GEMI), formerly SB-265805 and LB20304, is a newer fluoroquinolone with broad-spectrum activity against a wide variety of bacterial pathogens. The present investigation extended earlier observations by sampling an additional 6790 gram-positive organisms from more than 50 medical centres on three continents. The reference broth microdilution method with recommended medium supplements was used throughout. Selected results (number strains tested; MIC90 for GEMI/trovafloxacin in mg/l; % < or = 1 mg/l for GEMI/trovafloxacin) were: Staphylococcus aureus (3672; 2/2; 86/85), S. epidermidis (404; 1/>4; 92/71), Enterococcus faecalis (630; 4/>4; 76/66), E. faecium (216; > 4/>4; 15/11), Streptococcus pneumoniae (300; 0.06/0.25; 100/97), beta-haemolytic streptococci (150; 0.06/0.25; 100/100) and viridans group streptococci (150; 0.12/0.25; 99/97). Gemifloxacin appeared equal or superior to trovafloxacin in its overall gram-positive spectrum of activity pending a choice of the susceptible breakpoint concentration. Continued in vitro, pharmacodynamic and clinical investigations of gemifloxacin appear warranted.