High frequency of plant regeneration in sunflower was developed in order to use in modern sunflower breeding. Hypocotyl and cotyledon explants grown either in the light or in the dark of sunflower line and hybrids were investigated for their morphogenic potential on media containing a range of hormonal combinations including 1-naphthaleneacetic acid and 6-benzylaminopurine (0.5-1.5 mg/l). The amount of callus production in each explant was influenced by the age of seedlings from which the explants were taken, the type of explant, cultivars and the interaction between cultivars and light. Regeneration of embryo and shoot varied from 0% to 27% depends on the experiment. Although cotyledon explants taken from older seedlings produced statistically the lower amount of callus per explant, the morphogenic capacity of younger seedlings (4-day-old) was generally much higher than older seedlings.