OBJECTIVES: Tenofovir may be associated with nephrotoxicity. Several studies have shown that an early increase in urinary neutrophil gelatinase-associated lipocalin (NGAL) may predict the occurrence of acute kidney injury. We investigated urine and plasma NGAL in patients on long-term treatment with nevirapine associated with either tenofovir/emtricitabine or abacavir/lamivudine. PATIENTS AND METHODS: We studied 40 virologically controlled Caucasian patients on stable treatment (median >4 years) with tenofovir/emtricitabine + nevirapine (n = 20) or abacavir/lamivudine + nevirapine (n = 20), and no history of kidney disease, high blood pressure or diabetes. Plasma immunovirological parameters (NGAL and C-reactive protein) and urinary NGAL, beta2-microglobulin and alpha1-microglobulin were measured during a routine clinical visit. RESULTS: Median concentrations of NGAL were in the normal range, but were significantly higher in the abacavir/lamivudine group compared with the tenofovir/emtricitabine group both in the plasma, at 74.9 and 66.0 ng/mL (P = 0.032), respectively, and in the urine, at 36.1 and 12.8 ng/mL (P = 0.017), respectively. CONCLUSIONS: Plasma and urinary NGAL concentrations remained in the normal range in this long-term virologically controlld population without any overt renal disease. The usefulness of NGAL in detecting sub-clinical renal dysfunction appears to be very limited.