An analysis of the dispersion of a solute in a channel flow of fluid with couple stresses has been carried out. It is observed that couple stresses are more effective for&agr; < 20where&agr;is a nondimensional parameter. When&agr; > > 20, the effects of couple stresses on the dispersion of a solute are negligibly small. For&agr; → ∞, the dispersion of the solute is not affected by the couple stresses.