Experimental models based on the culture of cells within tridimensional (3-D) gels add a 3-D organization to the classical 2-D culture of vascular cells. They allow the study of cell structure in an environment which is more representative of the in vivo situation and the investigation of cellular functions which cannot be studied using the basic 2-D models. This review shows examples of the use of cultures of vascular cells (endothelial cells, smooth muscle cells as well as fibroblasts) in 3-D collagen matrices for the study of cellular functions as diverse as angiogenesis, extracellular matrix reorganization, migration through 3-D collagen gels or phenotype modulation. It also describes recent advances in the in vitro reconstruction of biological blood vessels by bioengineering. A method for the preparation of 3-D collagen gels is described.