The clinical efficacy of vascular prostheses depends largely on the histologic and functional characteristics of its induced tissue reactions. Various woven and knitted absorbable and partially absorbable compound polymeric prostheses were implanted into rabbit aortas to evaluate the effect of the prostheses on the regenerative and functional capabilities of repopulating endothelial and smooth muscle-like cells. Specimens harvested to one year were evaluated grossly and by light and scanning and transmission electron microscopy, compliance studies, and 6-keto prostaglandin F_1α (PGF_1α) assays. Results suggest that certain polymers may activate macrophages to induce a transinterstitial migration and proliferation of primitive mesenchymal cells which differentiate into cells with ultrastructural and functional characteristics of smooth muscle-like myofibroblasts and endothelial-like cells. Dacron® appears to inhibit these regenerative activities actively. Following total prosthetic reabsorption, conduits regenerated over polyglactin 910 or polydioxanone prostheses produced 6-keto PGF_1α and demonstrated strengths and compliances resembling normal aortic tissue. Clarification of factors controlling arterial regeneration should provide insights into the development of nonefficacious vascular prostheses and into the process of artherogenesis and myointimal hyperplasia.