An efficient protocol is outlined for the establishment of proliferating cell cluster cultures using a bioreactor, and subsequent regeneration of the aromatic plant, Lavandula angustifolia 'Munstead'. Red calli were obtained by culturing leaflet explants on basal MS medium supplemented with 0.23 mu M 2,4-dichlorophenoxyacetic (2,4-D) and 2.22 mu M 6-benzylaminopurine (BA), and subsequent sub-culturing. Calli were then transferred to basal MS liquid medium containing 0.23 mu M 2,4-D and 2.22 mu M BA to initiate suspension cultures. Cell clusters were obtained by sieving the initial suspensions and sub-culturing them in basal MS liquid medium supplemented with 0.23 mu M 2,4-D plus 2.22 mu M BA and 1.89 mu M abscisic acid, by means of shake culture, or bioreactor culture. After 20 d of culture, cell clusters were transferred to basal MS medium containing 1.14 mu M indole-3-acetic acid and produced a high number of regenerated plants, which were successfully transferred to soil.