The effects of secondary flow induced by a curved channel on fibrinogen deposition and replacement on a glass surface were studied. Platelet adhesion to surface-bound fibrinogen was also studied to indicate how secondary flaw may affect thrombogenesis on artificial surfaces. A saline pre-wetted channel with straight and curved sections was exposed to flowing plasma at a Reynolds number of 28.6. Results show that fibrinogen deposited on the surface at a shear rate of 175 s(-1) was replaced faster in regions of secondary flow (Dean numbers from 11 to 19) than in adjacent regions of shear flow. Platelets adhered only to those surfaces where fibrinogen had been detected.