Extracellular production of pigment was conducted in a culture of red beet hairy roots accompanied by pigment release under oxygen starvation. The phenomenon of pigment release into medium by oxygen starvation was found that a part of hairy root cells associated with a declination of cell viability decayed and the pigment release arose from the cells. The kinetics of pigment release was expressed by the declination of cell viability during oxygen starvation as the time response of first-order lag plus dead time, Moreover, the variation in cell viability affected the growth rate after oxygen starvation and the growth rate was evaluated by the extent of the decay of growing points in hairy roots. According to the kinetics, the culture accompanied by repeated pigment release was performed under oxygen starvation to achieve maximum extracellular production. From experimental data, the extracellular production rate was found to attain to 2.70 x 10(-4) kg/(m(3) . h)when oxygen starvation of 16 h duration was repeated three times.