Eleven new cases of Mycoplasma hominis infection occurring outside the genitourinary tract in adults not in the puerperium were evaluated in relation to the 25 cases previously reported. Cases of bacteremia (n = 14) were commonly associated with trauma or manipulation of the genitourinary tract and were often self-limited. Wound infections (n = 14) followed surgery by 4-14 days in most cases and may have arisen from contamination from the genitourinary or respiratory tract. Joint infections (n = 5) appeared to have resulted from bacteremic seeding in some cases and affected prosthetic joints in particular. Least frequent were central nervous system infections (one case of meningitis and two of brain abscess) and respiratory tract infections (three cases of empyema). The large majority of patients had fever, and infected fluid collections were commonly purulent. The response to therapy was difficult to assess in many cases, but responses to tetracycline, clindamycin, and drainage alone were observed. Identification of M. hominis requires clinical suspicion and alertness on the part of the bacteriology laboratory.