Objective This study aimed to describe the incidence and risk factors for the development of anterior uveitis in patients receiving intravenous cidofovir for the treatment of longstanding cytomegalovirus retinitis. Design The study design was a retrospective cohort. Participants Eighteen patients (30 eyes) receiving parenteral cidofovir for the treatment of complicated cytomegalovirus retinitis participated. Main outcome measures The clinical response to parenteral cidofovir; the occurrence of anterior uveitis, and the management and outcome of patients with this complication; and the effect of cidofovir on intraocular pressure measurements were measured. Results There was no progression or relapse of retinitis in patients receiving intravenous cidofovir. Eight (44%) of the 18 patients developed anterior uveitis, which occurred after a median of 4 doses of intravenous cidofovir. The median CD4+ cell count at the time of development of iritis was 101/mm 3. Patients who developed uveitis had a mean increase in serum creatinine over baseline measurements ( P = 0.05). The use of human immunodeficiency virus type-1 (HIV-1) protease inhibitors was not different between both groups of patients ( P = 1.0). The development of anterior uveitis and visually significant hypotony necessitated withdrawal of cidofovir in only one patient. Conclusions Anterior uveitis was a common complication after intravenous cidofovir therapy. Despite the frequency of this complication, continued treatment with intravenous cidofovir was possible in the majority of patients. Patients with anterior uveitis after intravenous cidofovir may be treated successfully with topical corticosteroid therapy and cycloplegic agents.