This paper examines how technology transfer within U. S. multinational firms changes in response to a series of IPR reforms undertaken by sixteen countries over the 1982–1999 period. Analysis of detailed firm-level data reveals that royalty payments for technology transferred to affiliates increase at the time of reforms, as do affiliate R&D expenditures and total levels of foreign patent applications. Increases in royalty payments and R&D expenditures are concentrated among affiliates of parent companies that use U. S. patents extensively prior to reform and are therefore expected to value IPR reform most. For this set of affiliates, increases in royalty payments exceed 30 percent.