This paper reports the development of a novel force measurement device based on polymeric nanopillar arrays. The device was fabricated by a process combining nanosphere lithography, oxygen plasma treatment, deep etching and nano-molding. Well-ordered polymeric nanopillar arrays with various diameters and aspect ratios were fabricated and used as cell culture substrates. Cell traction forces were measured by the deflection of the nanopillars. Since the location of the nanopillars can be monitored at all times, this device allows for the measurement of the evolution of adhesion forces over time.