In this experimental system we micro-surgically attach a custom-designed micro-flow chamber assembly to the carotid artery and jugular vein of a live mouse under anesthesia. This design creates a closed circuit with the animal’s circulatory system. The mouse’s native blood cells flow from the carotid artery, pass through the translucent area of the chamber for microscopy, and subsequently reenter the animal’s body through the jugular vein. The pressure gradient between the artery (high pressure) and the vein (low pressure) provides a continuous flow of cells through the chamber. Circulating peripheral blood leukocytes or platelets interact with immobilized molecules on the surfaces of the micro-fluidic chamber. Our technique allowed for the first time direct visualization of rolling and adhesion of unperturbed murine cells with individual proteins under native blood flow conditions, yet well-controlled experimental conditions.