We elucidated the relationship between cell proliferation and somatic embryogenesis in the culture of carrot cotyledons. Fresh weights of the cotyledon explants were determined every five days while being cultured on a medium containing 2,4-D. Callus produrtion increased exponentially from Day 20 to Day 25, showing a two-fold rate of proliferation. Tn examine the embryogenic potential of the callus, we pre-cultured cotyledon explants on an MS medium with 2,4-D, then transferred them to an MS basal medium at five-day intervals. Somatic embryos formed most frequently when the cotyledons were pre-cultured for 20 days on an MS medium that contained 5 $mu$M 2,4-D. The frequency of somatic embryo formation was 81%, while that of normal embryos with two cotyledons was 51% among those formed on a hormone-free medium. We used FACScan analysis to relate the embryogenic potential of the callus to the S phase in the cell cycle of cultured cells. The S phase was high after 25 days of culture on the medium with 5 $mu$M 2,4-D. In contrast, the frequency of normal embryogenesis was higher at Day 20 of the pre-culture period. Culturing embryogenic calli on a medium with 5 $mu$M 2,4-D was most favorable for producing somatic embryos with two cotyledons. We verified that active somatic embryogenesis was apparently related to tell division activity; somatic embryos induced from actively dividing tells were apt to accompany cotyledonary abnormality,