We build a new concordance between the NBER Patent Data and U.S. Census microdata and use it to examine what happens when firms patent. We find strong evidence that increases in patent stock are associated with increases in firm size, scope, and skill and capital intensity. We find somewhat weaker evidence that changes in patenting are positively correlated with changes in total factor productivity. We also analyze first-time patentees and find similar effects following initial patent application. Together, these results suggest that patenting is indeed associated with real changes within firms, in particular with growth through increases in scope.