Abstract Hirt, D. and G. W. Bernard. Calcitonin gene related peptides-beta unlike calcitonin gene related peptide-alpha, has no osteogenic stimulatory affect in vitro. Peptides 18(9) 1461–1463, 1997.—The purpose of this study is to test whether CGRP-beta has an osteogenic stimulating effect, as does CGRP-alpha, on rat bone marrow cells in vitro. CGRP-beta in different doses was added daily to bone marrow white cells, which were harvested from rats, then seeded onto a previously prepared layer of fibroblasts. CGRP-alpha in different doses was used as a positive control. Fourteen days after the start of the experiment, there was no statistical difference in the number of bone colonies between the control and CGRP-beta dishes. The CGRP-alpha dishes demonstrated an increase in the number of colonies with an increase of peptide dose.