Introduction: Kidney biopsy is a diagnostic method in which a kidney tissue sample is obtained, and whose analysis can provide data on the type and extent of the pathological process. We differentiate between open or surgical and closed or percutaneous kidney biopsies. Percutaneous kidney biopsy in local anesthesia is mostly performed. For visualization of the kidneys we use ultrasound and at the same time we follow the direction and position of the needle located in a special instrument. Objective: The aim of the study was to determine the most common indication for kidney biopsies, treatment outcomes and prognosis for treatment of patients with renal biopsy in the Zadar General Hospital in the period from 2012. to 2017. Methods and respondents: The study included 87 patients with renal desease, and their renal function was determined in the beginning, in the middle and at the end of the study, expressed in the values of creatinine and creatinine clearance and the value of proteinuria. The data were collected from the information system of the Zadar General Hospital. Results: Research has provided data showing that the prognosis of the disease depends on its etiology. It was also confirmed that patients with neat renal function have a better prognosis compared to patients with impaired renal function at the time of biopsies. Also, patients with higher proteinuria, or proteinuria at the level of nephrotic syndrome, have a poorer prognosis compared to patients with lower proteinuria values at the time of biopsy. Conclusion: The kidney biopsy is the most accurate method of analyzing the pathological process on the kidneys. Tissue analysis provides insight into the prognosis and progression of the disease, and therapeutic approach to the patient is also assessed.