This book constitutes the thoroughly refereed post-proceedings of the First International Symposium on Unifying Theories of Programming, UTP 2006, held at Walworth Castle, County Durham, UK, in February 2006.

The 14 revised full papers presented, including those by the six invited speakers, were carefully reviewed and selected for presentation at the symposium and went through a second round of improvement after the meeting. Based on the pioneering work on unifying theories of programming by Tony Haare and Jifeng He, UTP 2006 reaffirmed the relevance of the ongoing UTP project and advanced it by focusing on the most significant results and by raising awareness of the benefits of unifying theoretical frameworks among the wider computer science and software engineering communities.