A major goal of tissue engineering is to generate living cellular constructs with 3-D, tissue-like organization of cells and matrices. The generation of mechanical forces by the cellular cytoskeleton plays a critical role in the organization of matrix and of cellular colonies. The anchorage of the cytoskeleton to a substrate is essential for cellular tractional processes. We show that placing cells in scaffolds which contain a collagen-related synthetic peptide P-15 allows them to generate highly organized 3-D colonies and matrices. These observations suggest that P-15 may replicate cells' physiological collagen anchorage.