This study was conducted to determine the optimum planting dates and density of one year old Bupleurum falcatum L. to improve its productivity and quality. Two cultivars of B. falcatum, originated from Jeongseon, Korea and Mishima, Japan were used. Some of the results obtained are as follows : Jeongseon cultivar showed less stem branches and shoot weight compared to Mishima. However, Jeongseon cultivar showed tall plant height, high root fresh and dry weight, and high levels of saikosaponin, but low saikosaponin content than that of Mishima. Both cultivars seeded on March 20 had long main root, big stem diameter, few stem branch, and high saikosaponin c content compared to those of late seeded one, April 30. Growth characteristics such as plant height, stem diameter, stem branch number, shoot weight, root diameter, root fresh and dry weight, and root branch number were increased in a low planting $density(30;{ imes};15cm)$, but the content of saikosaponin was not affected by planting density. Jeongseon and Mishima cultivars seeded on April 10 with $30;{ imes};15cm$ planting density and April 30 with $30;{ imes};10cm$ planting density contained the highest total saikosaponin levels, respectively. However, average root dry weight were not affected by planting time or density in both Bupleurum cultivars.