A convenient model is presented which can be used to quantify the relationship between applied shear and attached cell fraction in cell/surface interaction studies The model uses two parameters (the shear stress required to detach the total attached cell population and a detachment constant) based on the estimated strength of the cell/bead interaction force. Use of these parameters allows results obtained on different systems to be compared. The model has been applied to data from three systems. 1) The effects of shear on the interaction between anti-goat IgG-coated beads and surface immobilized goat IgG;(1) 2) The effect of applying fluid shear stress to a stable fraction of attached 3T3 fibroblast cells on glass;(2) and 3) The interaction of suspended yeast cells with surface-immobilized concanavalin A which is reported here. In the yeast system the model provided a convenient aid for quantifying the effect of competing glucose on the interaction strength where it was found that the detachment constant for yeast interaction with surface-bound conA increases with the glucose concentration while the maximum shear stress and the binding force between the yeast cells and conA decreases.