Cloud Computing promises to deliver computational resources on demand as services that are commoditised and delivered as in traditional utilities such as electricity, gas, water and telephony. High Utility with Cloud services can already be achieved for compute, storage and communication resources but also for hosted software and data. UCC is the premier IEEE/ACM conference covering all areas related to Cloud Computing as a Utility. There is also increasing interest from commercial providers to offer business and revenue models around the services they offer. Understanding how these model could be used to provide utility for both users, intermediary brokers (aggregators) and providers will also be of interest for this conference. This will be the 6th UCC in a successful conference series. Previous events were held in Shanghai, China (Cloud 2009), Melbourne, Australia (Cloud 2010 & UCC 2011), Chennai, India (UCC 2010), and Chicago, USA (UCC 2012). UCC 2013 happens while cloud providers worldwide add new services and increase utility at a high pace and is therefore of high relevance for both academic and industrial research. Submissions are invited to UCC 2013. Please consult the Call for Papers and the complementary calls for Workshops, Tutorials and Industry Track Papers for formatting and submission details.