Aim: The aim of the present study was to evaluate retrospectively histopathologically-diagnosed lesions that were detected in the kidney after radical nephrectomy for a preoperative diagnosis of kidney cancer. Methods: The medical records of 83 patients (51 male, 32 female) were included. Preoperative staging was accomplished by various methods including physical examination, blood hemography and biochemistry, abdominal ultrasonography (US), chest x-ray, abdominal computed tomography (CT) and abdominal magnetic resonance imaging (MRI). Results: Totals of 70 patients underwent radical nephrectomy and 13 nephron sparing surgery. Of the 83 patients, 70 had malignant lesions (renal cell carcinoma, squamous cell carcinoma or other malignancies) 13 had a variety of benign lesions, the most frequently detected being oncoytoma (6), angiomyolipoma (3), xanthogranulamatous pyelonephritis (2), cortical cyst (1) and chronic pyelonephritic change (1). Conclusion: It was concluded that in spite of great technological developments regarding radiological imaging modalities such as US, CT and MRI, benign lesions might still be detected pathologically in patients who undergo radical nephrectomy with the preoperative diagnosis of renal cancer. But, all renal masses should be regarded as malignant and should be managed surgically otherwise proven benign.