The cavitation is a phenomenon that must be considered into a hydrokinetic turbines design. This assumption has been explored in the last years, principally for the turbine with large diameter, once the relative velocity near the hydrokinetic blade tip is increased, resulting in large angle of attack. Therefore, a mathematical approach for design of hydrokinetic blades is presented. In which a methodology for cavitation prevention is employed. The approach uses the minimum pressure coefficient criterion as a cavitation limit for the flow on the blades. The proposed methodology modifies the local relative velocity in order to prevent the cavitation occurrence on each blade section. The results are compared with data from hydrokinetic turbines designed using the classical Glauert's optimization, on which the proposed approach provides good performance, where the chord distribution along the blade is corrected, and can be used for efficient hydrokinetic turbines design.