Here we describe a simple approach to create various sizes of protein nanoarrays for the investigation of cell adhesion. Using a combination of nanosphere lithography, oxygen plasma treatment, deep etching and nanomolding processes, well-ordered polymeric nanopillar arrays have been fabricated with diameters in the range of 50-600nm. These nanopillar arrays were used as stamps for nanocontact printing to create fibronectin nanoarrays, which were used to study the size dependent formation of focal adhesion. It was found that cells can adhere and spread on fibronectin nanoarrays with a fibronectin pattern as small as 50nm. It was also found that the average size of focal adhesion decreased as the size of the fibronectin pattern was reduced.