In this study, production and optimisation of rosmarinic acid, a phenolic acid and an economically important metabolite, was investigated in the callus cultures established from the mature seeds of Satureja hortensis L. (summer savory) plant. Gamborg's B5 basal medium, supplemented with indol butyric acid (IBA) (1.00 mg L-1), N-6-benzyl aminopurine (6-BA) (1.00 mg L-1) and sucrose (2.5%, w/v), was employed for the establishment and maintenance of the callus cultures. Applications were individually prepared by preparing the media containing different IBA/6-BA combinations and sucrose concentrations. All of the applications were carried out in the continuous dark. In the applications, where the effects of IBA/6-BA combinations on the growth and rosmarinic acid accumulation were assayed (1-15 applications), the highest biomass yield was obtained from the medium supplemented with 1.00 mg L-1 IBA and 5.00 mg L-1 6-BA. In the case of the rosmarinic acid accumulation, an opposite relationship was determined between the growth and rosmarinic acid production. While the highest biomass yield was obtained from the medium containing 1.00 mg L-1 IBA and 5.00 mg L-1 6-BA, the highest rosmarinic acid accumulation was obtained from the medium supported with 1.00 mg L-1 IBA and 1.00 mg L-1 6-BA. In the applications where the effects of sucrose concentrations on the growth and rosmarinic acid accumulation were examined, the highest biomass yield was obtained from the medium which is supplemented with 5.0% (w/v) sucrose. In this category, the highest rosmarinic acid accumulation was obtained from the medium which is supported with 3.0% (w/v) sucrose. According to the experiments carried out with the wild S. hortensis, it is found to have 25.02 +/- 1.21 mg g(-1) rosmarinic acid. No differentiation was observed in any callus during the course of this study.