Increasing resistance to antimicrobial agents has occurred among many pathogens, but the emergence of resistant Streptococcus pneumoniae will have the greatest impact on the practice of outpatient medicine. Consequences of resistance include complicated management of acute otitis media and meningitis treatment failures. Pneumococci have acquired resistance to penicillin, third-generation cephalosporins and other antibiotics at an alarming rate; in some areas, 25 percent of isolates are nonsusceptible to penicillin. In areas with high resistance rates, the addition of vancomycin to cefotaxime or ceftriaxone is warranted for empiric treatment of bacterial meningitis. Changes in empiric therapy for pneumonia, bacteremia and otitis media may eventually be necessary. Previous antibiotic use is a risk factor for invasive disease with resistant pneumococci. Patients may be best protected by avoiding unnecessary use of antibiotics. Patient education materials as well as recommendations for avoiding the use of antibiotics for some upper respiratory tract infections are currently being developed to help physicians achieve this goal.