I explore the effect of M&A on the patenting quantity and quality of the firms involved in a deal. Three measures of quality are considered: impact, generality, and originality. The impact of a patent denotes its influence on future inventions. Generality refers to a patent's applicability across technological fields. Finally, the originality of a patent indicates the extent to which an invention synthesizes diverse technological inputs. Applying a matching estimator to data from the U.S. ‘medical devices and photographic equipment’ industry from 1988 to 1996, I find that M&A have a positive effect on patenting output, but decrease patent impact, originality, and generality. Copyright © 2011 John Wiley & Sons, Ltd.