Pathological, anatomical and patho-histological studies on cases of nephropathia with uncertain etiology in swine were performed in an industrial swine complex. Pathological, anatomical and patho-histological changes in the kidneys and in the regional lymph nodes were described. In accordance with the character and extent of the changes observed the kidneys were provisionally divided into four main groups. On the basis of the patho-histological findings the assumption is forwarded that agents of unknown toxic nature play an etiological role.