Experimental data on low-cycle fatigue of 304 steel and a VT9 titanium alloy in deformation by complex loading histories, which are the sequence of blocks of cycles of different shapes in the space of total strains, cited in the literature, are analyzed to develop adequate models for life calculations. The four damage accumulation rules and the low-cycle fatigue deformation criterion were used as basic approaches. Life prediction models were compared. It is shown that the application of a modified nonlinear damage accumulation rule can improve life prediction results, with better outcomes obtained for the programs involving nonproportional cycles.