The reliability of all-optical switches based on new approach is analyzed. The proposed approach allows to take into account three main criteria influencing on switch functioning such as switch architecture, switch technology and method of switching control. The mathematical expressions of the reliability functions and the mean time to failure of well-known all-optical switches have been obtained. The numerical results for reliability functions of Clos, Banyan, Dual and crossbar switches based on electro-optical basic elements are presented.