Agar dilution was used to determine the MICs of RPR 106972 (a new oral streptogramin), cefditoren (a new oral cephalosporin), two new oxazolidinones (U-100592 and U-100766), and other oral and parenteral agents for 203 penicillin-susceptible and -resistant pneumococci. All pneumococci were inhibited by RPR 106972 at < or = 0.5 microgram/ml. Cefditoren was very active against all pneumococcal groups, with MICs of < or = 2.0 micrograms/ml. Amoxicillin with or without clavulanate was the next most active oral beta-lactam, followed by cefdinir, cefuroxime, cefpodoxime, and cefprozil. U-100592 and U-100766 were very active against all classes of pneumococci, with all MICs < or = 1.0 microgram/ml.