SST-VEDI-1(VEDI-1) is a new synthetic compound which is synthesized from tryptamine. However, the effect of VEDI-1 on various bio-phenomena in cells has not yet been examined. Tryptamine is one of the known trace amines. Trace amines are present in the central nervous system at very low concentrations and they are generally considered to have potent sympathomimetic actions. On the other hand, SSH-BM-I and SSH-BM-II-type compounds have been demonstrated to stimulate osteoblast activity in the cultured scales of goldfish. These compounds are also synthesized from tryptamine. VEDI-1 has a similar chemical structure to that of SSH-BM-I and SSH-BM-II-type compounds. Therefore, this study examined the effect of VEDI-1 on osteoblastic differentiation. VEDI-1 inhibited the osteoblast differentiation identified by mineralization, which was accompanied by the down-regulation of the expression of an osteogenic transcription factor, Osterix (OSX). Furthermore, as well as VEDI-1-treatment, the suppression of the OSX expression by stable-transfection with OSX/shRNA decreased the formation of mineralized nodules. These results suggest a possibility that VEDI-1 inhibits the osteoblast differentiation by suppressing the OSX expression.