The proposal for the first 20 patients enrolled in ACTG 044 initially called for an open-labelled, pilot study of intravenous (IV) clindamycin and primaquine therapy in patients with mild to moderate PCP. Preliminary results of the first 22 patients entered into ACTG 044 indicate that the response rate to therapy was over 90 percent. The rate of discontinuation secondary to toxic side effects was only 20 percent. Additional uncontrolled studies have shown an excellent clinical response and safety profile in another 60 patients. The protocol has been amended to provide an all oral dosing regimen. An additional 20 patients with mild PCP will be enrolled and tested with oral clindamycin and primaquine on an outpatient basis. All patients will receive clindamycin and primaquine. Total duration of therapy will be 21 days. Patients may be hospitalized at any time during the study as clinically indicated. Treatment with zidovudine may be started or resumed after completion of clindamycin / primaquine therapy.