The objective of this study is to highlight the importance of renal biopsy in adult population (above 40 years age) with significant proteinuria due to renal diseases, so that accurate diagnosis and treatment plan can be devised. This is a retrospective study carrid out at the department of Nephrology, KTH, Peshawar. The biopsies carried out between June 1999 and June 2002 were scrutinized. All these were ultrasound guided percutaneous renal biopsies. Biopsies carried out in patients with the following findings were included in our study. 1. Nephrotic range proteinuria in adults. 2. non-nephrotic range proteinuria with evidence of hyptersion / haematuria / deranged renal fuction or active sediments or urine microscopy. 3. Patients having age above 40 years. 4. Patients not suffering from diabetes, chronic renal failure. Adult Polycystic Kidney disease, or any congenital renal disease. We conclude that in the adult population membranoproliferative GN is the leading histopatholgoical entity in middle aged population followed by membranous GN in our population. Percutaneous renal biopsy is a safe procedure. It helps us to determine the underlying histopathology for accurate diagnosis and guiding physicains in the management of such cases.