BACKGROUND We investigated the reliability and mapping of percutaneous needle core biopsies in the kidney in histopathological diagnosis of renal masses particularly for those with suspicious radiologic appearance in an attempt to prevent unnecessary nephrectomies. METHODS Overall, 96 cases were included in our study that underwent radical nephrectomy or partial nephrectomy due to renal mass between November 2007 - March 2010. Ex-vivo biopsies 1 cm apart were obtained from the peripheral region of the mass. Additionally, half of these peripheral biopsies were obtained from the central region of the mass. Diagnostic yield of the biopsy cores were correlated. Sensitivity and specificity of peripheral and central biopsies in differentiating benign and malignant tissues were calculated. RESULTS Sensitivity and specificity in differentiating malignant lesions were 93% and 87%, and 90% and 93% for peripheral and central biopsies, respectively. Positive and negative predictive values were 97% and 68%, and 98% and 64% for peripheral biopsies and central biopsies, respectively. Hazard ratio for cigarette smoking and presence of necrosis on CT scans were 4.76 (CI 1, 6-14.3; p = 0.04) and 3.32 (CI 1,2-9.2; p = 0.017) and 3.71 (CI 1.3-10.7; p = 0.013) and 3,51 (CI 1.3-9.6; p = 0.012) for peripheral and central biopsies, respectively. CONCLUSIONS Kidney biopsies can be performed in suspicious renal masses of central and peripheral biopsies with similar efficacy.