"Lyme nephritis" is a unique form of protein-losing nephropathy (PLN) with renal failure (RF) that has been reported in Lyme-positive dogs in endemic areas. Although depostiion of antigen-antibody complexes secondary to Borrelia burgdorderi infection is the suggested pathogenesis, no definitive evidence has yet been demonstrated to prove it. The aim of this study was to isolate antibodies against B. burgdorferi from renal tissues obtained from dogs with suspected "Lyme nephritis" to establish a cause-and-effect relationship between B. burgdorferi infection and the renal syndrome. Kidney samples were treated with the acid elution technique, and the eluates were evaluated for the presence of B. burgdorferi-specific antibodies using a kinetic ELISA (KELA) and Western blot. Positive KELA results as well as the formation of bands at 22, 31, 39, and 41 kilodaltons on Western blot confirmed the presence of B. burgdorferi-specific antibodies in kidneys.