Previous respiratory tract infections (RTI) and antibiotics consumption as possible risk factors for extended duration of PRP carriage were investigated in 24 children (cases) with previous carriage of penicillin-resistant pneumococci (PRP) for a duration exceeding 120 days (median 168 days) and a control group of 53 children with a duration of PRP carriage less than 90 days (median 21 days). The cases had experienced 0·99 episodes of acute otitis media (AOM) per life-year compared to 0·79 episodes in the controls (P=0·32). For antibiotic-treated RTI other than AOM, the corresponding numbers were 0·49 and 0·29 episodes per life-year, respectively (P=0·01). No differences in antibiotic consumption in the 3 months preceding the carriage, nor during the carriage period were noted. Other factors than impaired host defence to respiratory tract pathogens or antibiotics consumption seem to be more important in determining the duration of PRP carriage.