Bone and joint infections due to Streptococcus pneumoniae are uncommon in adults in the absence of risk factors (e.g. alcohol abuse, immunodepression, or preexisting joint disease). We report two cases in previously healthy adults. The clinical picture was septic arthritis of the knee in one patient and discitis with an extensive epidural abscess in the other. The characteristics of S. pneumoniae bone and joint infections are reviewed, with emphasis on risk factors. The therapeutic strategy is discussed in the light of the recent upsurge in S. pneumoniae strains with reduced susceptibility to penicillin.