In the design of structures, some unavoidable uncertainties must be taken into account. A procedure for the optimization of uncertain structures based on possibilistic reliability is presented in the paper. Some beneficial conclusions are obtained by contrasting it to the widely used traditional probabilistic ( stochastic) reliability based optimization. A practical numerical example shows that the results of optimization based on the two methods of possibilistic reliability and of probabilistic reliability are completely the same in the case of identical data information. This presents that both the possibilistic reliability model and the above mentioned optimization method are efficiency and feasible.