Taxus baccata L. is the main and almost the sole source of paclitaxel, which is an anti neoplastic agent and is used as a cure for treatment of breast and ovary cancer. Since production of this drug is almost a destructive process and yew is an endangered plant, it is required to optimize its tissue culture and micropropagation system. In order to produce embryo derived callus 16 combinations of two plant growth regulators 2,4-D (0, 0.5, 1 and 1.5 mg/L) and Kinetin (0, 0.1, 0.5 and 1 mg/L) were used to study its effects on callus formation and growth in Taxus baccata. It was determined that 1.5 mg/L 2,4-D + 0.1 mg/L kinetin was the best combination for callus growth. Increasing 2,4-D concentration, however, promoted callogenesis while kinetin only in a narrow range had positive effect on callus initiation.