Abstract: A gear shift control for bicycles, of the "derailleur" type which has guig members for a chain that can be moved crosswiss between at least two separate positions by a cable from a remotely located shifter, which includes a mobile element that receives the movement of the cable, a mobile toothed element connected to the guiding members of the chain, a memory element carried by the mobile element and working with the teeth of the mobile toothed element; and swinging members acting on the memory element so that, for a movement of the cable with a small amplitude, followed by a release, the toothed element is moved in a first direction along a path corresponding to the interval between two teeth, and for a movement of the cable of a greater amplitude, followed by a release, the toothed element is moved in a second direction also along a path corresponding to the interval between two teeth.