Abstract: The present paper deals with in vitro culture of immature sunflower embryos. The basic medium consists of modified White's medium, supplemented with thiamine 1 ppm, pyridoxine 1 ppm, nicotinic acid 1 ppm, Ca-pantothenate 0.5 ppm and glycine 3 ppm, and 4% sucrose and 0.8% agar were used throughout all the experiments. IAA and coconut milk (autoclaved) at different concentrations used singly or both mixed in various combinations were studied for their effect on embryo growth. The embryos isolated were about 5 mm in length and they usually germinate precociously when inoculated on the culture medium. The results are summarized as follows: 1. IAA (0.05–20 ppm) is stimulatory on the embryo growth as shown in the increase of fresh weight of the treated embryos. IAA is effective in inducing embryo callus. At the concentration of 1 ppm there are about one fourth embryos producing callus, at 5 ppm, about two thirds of embryos, and above 10 ppm, 100% embryos forming callus. IAA is stimulatory on the formation and growth of the root at low concentrations (0.05–0.1 ppm), but it becomes inhibitory on the root growth at higher concentrations (10–20 ppm). 2. Coconut milk (autoclaved) has definitely a pronounced favourable effect on the shoot growth of the embryo and it inhibits the root growth. Both effects are particularly conspicuous at the stage of two weeks old culture, thereafter the difference between the control and the treated embryos gradually becomes insignificant. Coconut milk is also effective in inducing embryo callus but it is not so effective as IAA. 3. The effects on growth and induction of embryo callus become more pronounced when IAA and coconut milk are mixed in various combinations for treatment. There are certain similarities between the effect of coconut milk and that of IAA but it is im- probable that the effective substance in coconut milk is only an auxin.