The effect of pulsation on the overall mass transfer coefficient between a sphere and a liquid at low Reynolds number (Re < 6.36) has been studied. When there is no flow reversal, pulsations have a negative effect on the mass transfer coefficient, it being minimum when the dimensionless group alpha = alpha omega/u(0) = 1. When flow reversal occurs the mass transfer coefficient increases with both frequency, f, and amplitude, a, of the pulse and decreases with the mean fluid velocity, u(0). The variation of the mass transfer coefficient has been studied with a model based on the quasisteady-state assumption. In this way two correlations have been obtained for the mass transfer coefficient : Re < 20 Sh=1.23Sc(1/3)Re(0.23) Re > 20 Sh=0.39Sc(1/3)Re(0.58)