Indoleacetic acid (IAA), gibberellic acid (GA3), and kinetin were incorporated into tissue culture media to determine the effective concentrations for sustaining growth of excised immature tomato (Lycopersicon esculentum Mill.) embryos. GA3 (10-7 to 10-5 M) stimulated growth of 13- and 15-day-old embryos but resulted in morphological abnormalities. Kinetin (10-8 or 10-7 M) promoted embryonic development and expansion of cotyledons but inhibited subsequent growth. Combinations of kinetin and GA3 or kinetin and IAA were most beneficial for embryos excised 12 days after pollination, when embryonic development was at a globular to early heart-shaped stage.