Seed vigor is the plant-producing ability of a seed in the field. This study was conducted to determine if radicle area could be used as a quantitative test for screening the vigor of pepper (Capsicum annuum L.) seeds. 'SPP7117' pepper seeds were primed with a synthetic calcium silicate (MicroCel E) and water at 30° C for five days. Seeds were aged for 0, 7, 14, and 21 d at 42° C and 95% relative humidity. Primed and nonprimed vigor was evaluated by radicle area as well as germination and emergence characteristics. Excised radicles were incubated at 25° C and visible area was recorded in the range of 6-96 h. The results showed that seed priming significantly increased final radicle area, while aging decreased it compared with nontreated control. A 48-h incubation period of excised radicles at 25° C was found to be sufficient to differentiate seed vigor in primed or aged pepper seeds. Furthermore, radicle area showed a strong positive correlation with final germination of control (R 2=0.89) and primed (R 2=0.98) seeds. These results suggest that radicle area is an effective technique and can be used for judging the quality of pepper seeds.