In this open-label, randomized, parallel-groups study the Authors compare the parenteral administration of a beta-lactamase inhibitor associated with a semisynthetic penicillin (sulbactam-ampicillin) with the oral administration of a 3rd-generation quinolone (ofloxacin), in 20 HIV-infected subjects suffering from lower respiratory tract (LRT) infections. 12 patients were classified as AIDS, 6 as ARC (AIDS related complex) and 2 as asymptomatic seropositives. The risk of becoming HIV-infected and the work load for the health staff were also evaluated. The clinical and microbiological results indicate that oral ofloxacin is as effective as parenteral sulbactam-ampicillin for the treatment of LRT infections in HIV-positive individuals. In addition, the members of the health staff reported significantly less difficulty in administering ofloxacin in respect to sulbactam-ampicillin.