This contribution deals with the design of cross flow water turbines. The mechanical stress sustained by the blades depends on the basic geometrical specifications of the cross flow water turbine, its rotational speed, the exact geometry of the blades and the velocity of the upstream water current. During the operation, the blades are submitted to severe cyclic loadings generated by pressure field's variation as function of angular position. This paper proposes a simplified design methodology for structural analysis of cross flow water turbine blades, with quite low computational time. A new trapezoidal-bladed turbine obtained from this method promises to be more efficient than the classical designs. Its most distinctive characteristic is a variable profiled cross-section area, which should significantly reduce the intensity of cyclic loadings in the material and improve the turbine's durability. The advantages of this new geometry will be compared with three other geometries based on NACA0018 hydrofoil. (C) 2009 Elsevier Ltd. All rights reserved.