A 58-year-old man admitted for fever, nausea, vomiting, and anuria after the start of HAART, including tenofovir, had a viral load of 1.1 x 10(5) copies/mL, a CD4-positive lymphocyte count of 81/microL, and serum creatinine of 0.8 mg/dL before HAART. He underwent renal biopsy and temporary dialysis. We concluded that the patient had acute tubular necrosis because of potentially impaired renal function and the high amount of medication, and judging from the renal biopsy specimen and clinical course. When implementing HAART, physicians should be aware of and monitor potential patient misunderstanding of instructions on dosage and administration and for possible complications in medicinal combinations and potential side effects. TDF taken together with lopinavir may increase the plasma concentration of TDF or other medications that could worsen renal function. It should also be noted that renal dysfunction is a potential complication in the elderly.