The sucessful incorporation of extracorporally engineered tissue into critical size bone defects (CSD) entails an optimal compound of a tissue matrix and the incorporated specific cell types. The aim of this study was the development of a primary vascularised implant construct on the basis of a fibrin matrix and autologeous cells and tissue components to restore CSDs ad integrum. For this reason fibrin matrices were engineered from veneous blood from Göttinger minipigs using the Modidified Critical Point Dry (MCPD) - method and stored at - 20° Celsius for further use. Osteoblast were gathered from the periost of the scull while the endothelial cells were cultured from jugular veins of the pigs. The defrosted matrices were incubated with the cells an controlled in vitro for proliferation, adhesion and differentiation using histological, immunohistological and ultrastructural techniques. In vivo constructs of three incubated matrices were sandwich-like incorporated in artificial CSD. Bone regeneration was controlled at specific times after 3,7 and 14 days past incorporation again using histological, immunohistological and ultrastructural techniques. In vitro both cell lines showed a clear adhesion on the matrix only few hours after colonization and increased proliferation with confluent cell layers after 3 days. Osteoblast proved an increased expression for extracellular matrix proteins while the endothelial cells started to build cyclic structures after confluence and cell-to-cell contacts. The in vivo results a condensed, accelerated regeneration in the CSD with endothelial sprouting into the defects after 3 days and osteous mineralisation areas in the fibrin network. 14 days past incorporation the CSDs were nearly completely filled with new bone formation. The bone regeneration in the MCPD-Fibrin sprouted twice as fast as in the controll groups. Regarding the results of the study fibrin is an ideal matrix for solely outologeous bone tissue engineering with precise advantages concerning cell behaviour an defect incorporation in comparison to alternative constructs. Keywords: autolog, tissue engineering, fibrin, angiogenesis, osteogenesis, osteoconduction