To study the possible effect of collagen cross-link formation on the lamellar bone deposition, isolated mouse bone cells were transplanted in the syngeneic system and the formation of bone was followed in control and beta-aminopropionitrile (BAPN) treated animals. Woven and lamellar bone were distinguished by shape of bone lacunae, PAS reaction and Sirius red staining of collagen fibers. BAPN was administered in various doses either subcutaneously or in drinking water. Bone formed in BAPN treated animals contained both woven and lamellar bone in similar proportion as in controls. Thus, cross-linking of collagen seems to be unnecessary for lamellar bone deposition.