On the basis of the own experimental studies of power consumption and heat transfer, four basic types of high speed agitators which were located vertically and horizontally in the agitated vessel with or without baffles have been compared. A comparative criterion was the optimization coefficient K. The most optimal agitator is a side-entering propeller agitator in the non-baffled agitated vessel. Basing on the criterion K, the optimal geometric parameters of this agitator have been determined.