Changes in starch content and activities of ADPG- and UDPG-starch synthase and $alpha$- and, $eta$-amylase were studied in order to investigate effects of gibberellic aicd and abscisic acid on endogenous starch content during shoot differentiation and protocorm propagation in Cymbidium spp. (Jungfrau) protocorm. Shoot differentiation was promoted during the degradation of endogenous starch and protocorn propagation was promoted during starch accumulation in protocorm. The activities of ADPG- and, UDPG-starch synthase and $alpha$- and $eta$-amylase seemed to be related with starch content. Shoot differentiation and protocorm propagation were slightly inhibited in protocorm explants treated with 100$mu$M gibberellic acid. The explants treated with 10$mu$M abscisic acid lost the capacity for shoot differentiation and protocorm propagation, and that could not be overcome by 100$mu$M gibberellic acid added to culture medium. Starch content fluctuated as the control even after 10$mu$M abscisic acid. None the less, the treatment completely inhibited shoot differentiation and protocorm propagation.