The influence of particles, both coherent and noncoherent with the matrix, on the work hardening of metals and alloys is examined. The interaction between dislocations and particles, which leads to the crossing or bypassng of particles by dislocations, is discussed. Methods of evaluating the linear dislocation stress, the forces interacting between the dislocations and the particle, and also the effective distance separating the particles are presented. The determination of these values makes it possible to calculate the critical shear stress of an alloy containing the particles. The effect of cold working on strain hardening of an alloy containing particles is also discussed.