This study was conducted to determine the contents of astragalosides in Astragalus membranaceus. The total astragaloside content ($1701{mu}g;g^{-1}$) of 2 year-cultivated astragalus was the highest among the variously cultivated astragalus plants. Upon an increase in cultivation time, the average value of the total astragaloside content decreased (from $1650{mu}g;g^{-1}$ to $645{mu}g;g^{-1}$). Especially, the content of astragaloside decreased rapidly. Comparison between the top and subterranean parts of harvested astragalus plants showed that as the cultivation time increased, the astragaloside content of the top part decreased. On the other hand, the subterranean part demonstrated the opposite pattern. The astragaloside content of the top root increased compared to that in the lateral root (from $1.9{mu}g;g^{-1}$ to $33.4{mu}g;g^{-1}$). Further, the content of astragaloside increased in the top root as the cultivation time increased.