The aim of our study was to re-evaluate the in vitro activity of cefpodoxime in comparison with other oral beta-lactam antibiotics against bacteria causing respiratory tract infections. The study drugs were cefpodoxime, cefaclor, cefixime, cefuroxime, cefetamet, cefprozil, and the combination of amoxicillin and clavulanic acid (= augmentin). In addition, cefotaxime as the standard agent of parenteral third generation cephalosporins was examined. The organisms tested were Staphylococcus aureus, Streptococcus pyogenes, Streptococcus agalactiae, streptococci of serogroups C and G, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Proteus mirabilis. Minimal inhibitory concentrations of the antimicrobials were determined with the agar dilution procedure. Cefpodoxime showed the broadest spectrum and generally also the highest activity of the oral beta-lactam antibiotics examined. The drug was equally active against the major groups of beta-lactamase negative and positive bacteria causing respiratory tract infections. Against penicillin-resistant pneumococci, all beta-lactam agents exhibited reduced activity comparable to the reduced activity of penicillin.