OBJECTIVE: Indinavir is a proteaseinhibitor used in the treatment of HIV with a lithogeniccapacity as a urological side effect. The pathogenesis,diagnosis and treatment of indinavir urolithiasis are brieflyreviewed.METHODS: A 37-year-old male, seropositive for HIVon treatment with indinavir, lamiduvine and zidovudine,consulted for colicky left lumbar pain, nausea, vomitingand dark urine for the past three days.RESULTS: Patient evaluation showed a nonfunctioningleft kidney and ureterohydronephrosis of unknown origin.URS showed a yellowish, friable material with a mucinousappearance that occupied the entire lumen of the ureter.Fragmentation was achieved with the lithotriptor probe.Six months later the patient had fully recovered and wasasymptomatic.CONCLUSIONS: The incidence of protease inhibitor-induced urolithiasis is increasing. This condition should bedistinguished from uric acid calculi whose treatment willaggravate the indinavir urolithiasis