A new approach for the design of a molecular rectifier is proposed. Using a simple model, we have shown that conformational changes induced by the electric field may lead to a rectifying junction. The simplest possible rectifier of this kind presents two almost isoenergetic conformations, with different conductances and dipole moments. A simple equation allows for the estimation of the range of molecular parameters and temperatures that lead to an effective rectification. Examples show that rectification based on this mechanism is also possible at room temperature.