Fluoroquinolones, especially the newer agents, have an increased role in the management of respiratory tract infections worldwide. In the SENTRY Antimicrobial Surveillance Program for the Asia-Pacific Region for 1998 and 1999, 630 Streptococcus pneumoniae, 583 Hemophilus influenzae and 274 Moraxella catarrhalis isolates were examined to determine the comparative activity of the new fluoroquinolone, gatifloxacin, compared with those of ciprofloxacin, levofloxacin and trovafloxacin. Gatifloxacin was highly active against all three species. Decreased susceptibility (MIC >/=2 microg/mL) to gatifloxacin was noted in only seven strains of S. pneumoniae (3 of which were resistant); in three strains of H. influenzae (MIC >/= 0.12 microg/mL), and 2 M. catarrhalis (MIC > 2 microg/mL).