What is CMSUK? The Case Management Society UK (CMSUK), is a non-profit association of Case Managers, committed to the delivery of quality case management through standards of best practice while promoting the individual and collective development of case management throughout the United Kingdom. CMSUK is a charitable company, we became incorporated on 3 July, 2001 and registered as a charity on 6 February, 2006. As a charity our purpose is to protect and promote public well being.