BK-virus nephropathy was recently recognised as a new complication that affects renal allografts and causes dysfunction. We report a case of a recipient of simultaneous kidney-pancreas allografts. Fourteen months after the transplant, the renal allograft became dysfunctional with elevation of serum creatinine level. The diagnosis of BK-virus nephropathy was established by needle renal biopsy with immunohistochemical detection of human polyoma virus. Immunosuppressive therapy was reduced but progressive dysfunction developed and the patient had to undergo a renal retransplantation 11 months after the diagnosis of the infection. Due to repeated renal dysfunction, needle biopsy was performed, and the diagnosis of repeated BK-virus nephropathy was established six months after the retransplantation. The pancreas allograft has functioned well for the entire period.