This report contains the proceedings of The 19th Automated Reasoning Workshop (ARW2012). The workshop was held at the University of Manchester from 2 to 4 April 2012. ARW provides an informal forum for the automated reasoning community to discuss recent work, new ideas and applications, and current trends. It aims to bring togetherresearchers from all areas of automated reasoning in order to foster links and facilitatecross-fertilisation of ideas among researchers from various disciplines, from theoreticians,from implementers and from users of automated reasoning methodologies. Since 1994, when it was held in Leeds as part of the 1994 AISB Workshop and Tutorial Series,ARW has been organised on an annual basis.