The metabolism of [$^{14} extrm{C}$] $ extrm{GA}_{12}$ in the Chinese yam (Dioscorea opposita Thunb. var. Tsukune) was examined to determine the identification of endogenous gibberellins. [$^{14} extrm{C}$] $ extrm{GA}_{12}$ was metabolized to $ extrm{GA}_{53}$, $ extrm{GA}_{44}$, $ extrm{GA}_{19}$, $ extrm{GA}_{20}$, $ extrm{GA}_1$, $ extrm{GA}_8$, $ extrm{GA}_{15}$, $ extrm{GA}_{24}$, $ extrm{GA}_9$, $ extrm{GA}_{36}$ and $ extrm{GA}_4$. Radioactivity of GAs in non C-13 hydroxylation route was five-fold higher than that of early C-13 hydroxylation in analyzed GA-metabolites. Radioactivity of $ extrm{GA}_4$ was always four times higher than that of $ extrm{GA}_1$ at every feeding time. $ extrm{GA}_1$ radioactivity has always a lower level to below 200 DPM. The major pathway of endogenous GA metabolism in seedlings of the Chinese yam might be the non C-13 hydroxylation pathway.