Objective Colistin is frequently used in intensive care units due to gram-negative microorganisms that are multi-drug resistant causing hospital-acquired infections. Colistin-related nephrotoxicity is a common side effect. In this study, we aimed to examine the general characteristics, treatments and outcomes of patients who developed renal replacement therapy (RRT) need due to colistin nephrotoxicity in the intensive care unit. Materials and Methods Age, gender, diagnosis of ICU admission, additional diseases, culture locations and microorganisms grown in culture, Acute Physiology, Assessment and Chronic Health Evaluation (APACHE II) score and Carlson Comorbidity Index (CCI) scores were recorded during admission to intensive care unit. Then, the laboratory parameters of the blood samples taken on the day the patients started colistin therapy and the day the treatment was terminated were recorded. In addition, the day of initiation of colistin therapy, total dose of colistin given, hemodialysis need of the patients, total intensive care hospitalization day and mortality rates were recorded. Differences in clinical and laboratory data between groups were evaluated statistically. p <0.05 is considered significant. Resulrs It was observed that the need for renal replacement therapy developed in 33% of patients using colistin in the intensive care unit. Pre-treatment creatinine values were determined as indepen- dent risk factors for RRT. Apart from this, the age of the patients, APACHE II scores, urea and eGFR values before colistin therapy, colistin treatment dose and total colistin administration day, renal replacement therapy need were determined. Conclusion The need for RRT related to colistin therapy is common. Pre-treatment creatine levels were found to be an independent risk factor for the development of RRT.