This book constitutes the refereed proceedings of the 10th International Conference on Agile Processes in Software Engineering and Extreme Programming, XP 2009, held in Sardinia, Italy, in May 2009.

Out of 40 paper submissions 12 full papers were accepted for publication in this book together with 2 keynote papers, 11 short papers, 23 workshop and tutorial papers, 5 posters, 6 demonstrations and information on 3 panel discussions. The papers represent a set of high-quality research studies addressing a wide variety of different topics, ranging from very technical issues to human-related aspects of agile software development, including novel ideas on agile software research.