Fibrin proliferation from both human fibrinogen solutions and platelet-poor plasma was studied quantitatively as a function of substrate surface properties. A quartz crystal microbalance was used to monitor both protein adsorption and fibrin proliferation in real time at hydrophobic, hydrophilic, positively charged, and negatively charged surfaces. Scanning electron microscopy was used to characterize the morphology of the polymerized fibrin layers. The observed changes in mass indicate that fibrinogen adsorption occurs rapidly and mediates subsequent fibrin proliferation. Notably, substrate surface properties significantly affect the ability of adsorbed fibrinogen to promote fibrin proliferation.