A general approach is presented for generating pin-jointed compliant mechanisms considering geometrical nonlinearity. An optimization problem is formulated for minimizing the total structural volume under constraints on the displacement at the specified node, and stiffnesses at initial and final states, where the design variables are cross-sectional areas and the nodal coordinates. It is shown in the numerical examples that several mechanisms can be naturally found as a result of optimization starting from randomly selected initial solutions. The effect of extensional and compressional stiffnesses on the optimal solutions are also discussed. It is also shown that no local bifurcation point exist along the equilibrium path, and the obtained mechanism is not sensitive to intial imperfections.