A low frequency dielectric study of glass-forming maltitol and sorbitol has been performed. It enables us to show an. effect of a side branching on the sub-T-g relaxation curves. This molecular complexity has no effect on the temperature evolution of the secondary relaxation times of both compounds, which superimpose perfectly. However, side branching leads in maltitol to a sharpening of the corresponding distribution and occurrence of an intermediate strongly activated process, which has no separate secondary counterpart.