While we would expect that cross-border patents are used to protect a technology that is made available in another country, that technology could either be produced locally or imported. International patent filings could therefore be either complements or substitutes to international trade. This study combines data on patenting and trade for 149 countries and 249 industries between 1974 and 2006 with a “three-way” panel data model that addresses several biases emphasized in the trade literature in order to provide a systematic analysis of how bilateral trade responds to cross-border patent filings. We find that cross-border patents have a positive (complementary) overall effect on the patent-filing country’s exports to the patent-granting country and no effect overall on imports flowing in the opposite direction. These effects vary substantially across industry groups, with patents promoting significantly more export growth in industries with a high demand elasticity and in industries that are relatively more downstream in supply chains. We also find that patents, once obtained, are associated with increased trade even in jurisdictions with weak intellectual property regimes