Forces exerted on adherent calls by fluid shear stresses can cause cell detachment. In this study, we examined the effect of cell spreading, actin fiber density, and the conformation of adsorbed adhesion proteins in promoting cell adhesion after a brief exposure to shear stresses between 5-80 dyne/cm2 in a parallel plate flow channel. Cell spreading led to increased adhesion. Cell spreading and adhesion were greater when the surface contained preadsorbed fibronectin. Spreading was accompanied by formation of cytoskeleton which strengthened the adhesive contact between the cell and surface. Similar numbers of cells were detached from hydrophobic and hydrophilic glass containing preadsorbed in even though the cell binding domain was in different conformations.