Nephropathy caused by poliomavirus (BKVAN) in transplant recipients is responsible for the loss of the transplanted organ. In this study we suggest a non-invasive diagnostic protocol for the early identification of BKVAN during follow-up treatments. In 117 kidney transplant recipients follow-up was performed every three months during a two year period after transplantation and a positive screening result was confirmed and assessed by quantitative assays (BKV DNA load in plasma and urine). The definitive diagnosis of BKV requires allograft biopsy. Of the 117 patients 4 had BKVAN (3.4%), and the consequential reduction of immunosuppression improved kidney function and plasma clearance of the virus was achieved.