The contents of lignan, protein, and oil of nine Sesamum indicum cultivars were analyzed. To determine the lignan contents, sesamin 1 and sesamolin 2 were isolated from the ethylacetate extracts of the Suwon cultivar, and the structures were fully characterized by spectral and physical methods. The seeds of nine cultivars were screened for two lignans, which were determined by HPLC using a $C_{18}$ reversed phase column coupled with a photodiode array detector. Suwon cultivar showed the highest concentration (1: $6.24{pm}0.04$ and 2: $3.58{pm}0.01;mg/g$), whereas Soonheuk displayed the lowest (1: $0.91{pm}0.01$ and 2: $0.73{pm}0.01;mg/g$). The average content ratio of sesamin 1 (3.64 mg/g) was significantly higher than that of sesamolin 2 (2.57 mg/g). The protein content ranged from $21.52{pm}0.35$ to $31.22{pm}0.25%$, Suwon containing the highest level and Soonheuk had the lowest. Kwangbaek showed the highest oil level ($49.84{pm}0.40%$), while Soonheuk exhibited the lowest ($42.52{pm}0.05%$). Sesamin 1 exhibited a stronger radical-scavenging activity in the ABTS ($IC_{50}:;63.2{pm}2.4;{mu}M$) than its DPPH radical-scavenging activity ($IC_{50}>200;{mu}M$). These results lead to the conclusion that lignan content is affected by protein and oil contents. Concentration of the chemical components in the cultivars could be a key factor in the selection process of a high quality species.