Characteristics of power consumption in an agitated vessel with an "EGSTAR" agitator, which has been practically used as a bioreactor, are clarified experimentally. The power consumption at nonbaffled condition was well correlated with the friction factor and the modified Reynolds number, in a similar manner to Kamei et al. (1995) for a paddle impeller. In this work, the parameter gamma n(p)(0.7)b/H for the paddle impeller is modified to 1.5 gamma(d/H) (h(d)/d)(0.59) for the EGSTAR agitator. The power consumption under baffled conditions was also correlated well with the correlation method, similar to Kamei＇s method. The fully baffled condition and the corresponding power number for EGSTAR agitator are presented by the following equations. (B-w/D) n(b)(0.8) greater than or equal to 0.74 (h(d)/d) (0.12) N-Pmax,N-epsilon = 3.7 (h(d)/d)(0.59) (1-epsilon)(-1.1).