We cordially invite you to attend the 9th International Conference on Rough Sets and Knowledge Technology (RSKT 2014) to be held in Shanghai, China, October 24-26, 2014. The conference will be held at Tongji University. In keeping with the aims of the past conferences, RSKT 2014 provides opportunity to explore synergies between rough sets and state-of-the art knowledge technologies, in terms of both foundations and applications. Rough Set and Knowledge Technology (RSKT) is a series of annual conferences on the subject of rough sets and knowledge technology spanning over last eight years. Its aim is to present the state-of-the-art scientific results, encourage academic and industrial interaction, and promote collaborative research in rough sets and knowledge technology worldwide. Previous RSKT conferences were successfully held in Halifax, Canada (2013), Chengdu, China (2012), Banff, Canada (2011), Beijing, China (2010), Gold Coast, Australia (2009), Chengdu, China (2008), Toronto, Canada (2007) and Chongqing, China (2006).