Aside from effective antiretroviral therapy, there is no consistently effective antiparasitic therapy for cryptosporidiosis in AIDS. The purpose of this study was to assess safety, efficacy, and durability of combination therapy with paromomycin and azithromycin for chronic cryptosporidiosis. Patients with AIDS, chronic cryptosporidiosis, and 99% at 2, 4, and 12 weeks, respectively. None of the responses were attributable to antiretrovirals. Of 5 survivors at 12-30 months of follow-up, 3 remain asymptomatic off medications, and 2 have chronic, mild diarrhea. Treatment of cryptosporidiosis with azithromycin and paromomycin was associated with significant reduction in oocyst excretion and some clinical improvement.