The principal aim of our work was to study the mechanisms of urothelial differentiation and to examine the role of several proteins (fe. uroplakins) involved at particular stages of the development of terminally differentiated surface urothelial cell. Understanding of the mechanisms involved in cell differentiation can also be applied to wound healing and to the detachment and regeneration of the epithelium. In other words development of the various techniques may be expected to be of benefit in others important fields of research and not be restricted to the bladder alone. This all represent an important developing research field in Slovenia where we combine research capacitive of Medical faculty with clinical department of Urology.