In real conditions, a great majority of machine and elements and parts are subjected to cyclic deformation. There is no possibility to improve their quality, to increase their reliability and durability without good knowledge of working condition and materials feature. During cyclic loading, stresses can overpass proportionality limits. It causes residual stresses which reduce durability of elements to limited number of loading cycles. Such a loading is called low cycle loading. Usually it happens in small volumes of material, concentration zones, welded joints so on. In this work, main cyclic elastic plastic characterestics of materials are presented and explained. It also contains experimental and analytical methods of estimation that characteristics and detail research of experimental cyclic stress strain curve approximation methods.