Background/aim: Colistin is gaining popularity against multidrug-resistant bacteria. The primary concern with colistin is its nephrotoxicity (NT). The aim of this study was to evaluate the incidence and risk factors for NT and to evaluate the risk factors for mortality in the toxicity group. Materials and methods: NT was defined according to the RIFLE criteria. Data of patients who did or did not develop NT were compared. Positive and negative predictive values, risk ratio, and correlation coefficients were calculated. Results: NT was seen in 39 patients (70%). Hypoalbuminemia, old age, and the use of vasopressors (VPs) were associated with NT. The use of VPs had the highest positive predictive value, while age had the highest negative predictive value and risk ratio. The only variable that was associated with mortality in the toxicity group was VP use. Conclusion: Aging, hypoalbuminemia, and the use of VPs were shown to be risk factors for NT, while the last of these was the only significant risk factor for mortality in the toxicity group.