Within the scope of a piecewise homogeneous body model, with the use of the three-dimensional linearized theory of elastic waves in prestrained bodies, the effect of initial strains in layers on the dispersion of torsional waves in a hollow sandwich cylinder is studied. Two cases are considered: in Case 1, it is assumed that initial strains exist in only face layers; in Case 2, initial strains occur in all layers of the cylinder. The elasticity relations for layer materials of the cylinder are given through a harmonic potential. A dispersion equation is derived, and an analytical expression is obtained for the limit values of wave propagation speed for low wave numbers. Numerical results are presented and discussed.