The most severe spleen lesions with conquasation and devascularisation of entire organ, when it is practically impossible to do any preservating surgical procedure, are the true indications for the transplantation of this extremely important immunological organ. We have performed the evaluation of the surgical procedure of heterotopic auto transplantation in the 30 dogs with severe spleen lesions. Simulation of totally devascularized spleen with the lesions of V degree was performed by disrupting all segmental blood vessels with deep and long longitudinal transhilar incision. During the 3 months follow-up period, animals were subjected to numerous explorations in order to macroscopically and histologically valuate the implant. In most cases (80-85%) implants had complete vitality with the preservation of normal tissue architecture, while 15-20% of implants had partial or total fibrosis. There were no mortality and no complications after this preservation procedure. The presence of fibrosis in some implants suggests that the implant preparation should be better performed and that transplantation of larger tissue volume is needed. Enriched with this experimental experience we have performed heterotopic auto transplantation in 2 patients with spleen lesion of V degree (car accident and injury at work) with very satisfactory results.