Meropenem, a new parenteral carbapenem demonstrated increased activity as compared to imipenem against 336 strains of Neisseria gonorrhoeae, 119 strains of Haemophilus influenzae, and 110 strains of H. ducreyi. Neither carbapenem was affected by the beta-lactamase activity of the organisms tested. Ceftriaxone and ciprofloxacin demonstrated activity superior to that of both carbapenems while the activity of ceftazidime was similar to that of meropenem.