In a comparison of suture and fibrin bonding (using human plasma fraction Cohn I) direct as well as autologous and homologous nerve transplantations were performed in animal experiments. The study was carried out in a total of 66 Nn. ischiadici in Albino Wistar rats. With and without transplants the anastomoses were provided 26 times with the usual microsurgical single-button suture technique and 11 times tith a fibrin adhesive cuff with sequential application of the two components (500 I. U. thrombin/ml, 3,000 units contrycal) or simultaneous application after premixing of the components (5 I. U. thrombin/ml, 50 units contrycal). The qualitative evaluation was carried out after 4, 6, and 12 weeks according to the clinical and histological findings. With the use of sufficiently long transplants the nerve anastomoses could be fixed sutureless with the adhesive cuff more simply than with sutures. Histologically an undisturbed growing forth of the axons without foreign-body reactions and scarred constrictions could be proved. The sutured anastomoses, too, showed a good regeneration; owing to the 2-3 single button-sutures only low-degree tissue reactions occurred around the threads without any greater impairment of the proliferation of the neurites. In case of the direct uniting of the nerves adhesion was only possible in combination with a holding suture. In most cases, however, anastomose dehiscences with a bad result were nevertheless found. The direct nerve suture had to be carried out with 5-7 single-button sutures. In this case, considerably pronounced foreign-body reactions were sometimes found histologically. The nerve regeneration, however, was much better than in case of bonding by adhesion. In contrast to the application in direct nerve joining, the Cohn I adhesive could be used with good results for nerve transplantations.