This book constitutes the refereed proceedings of the 13th International Workshop on Groupware, CRIWG 2007, held in Bariloche, Argentina. The 17 revised full papers and 10 revised work-in-progress papers are organized in topical sections on group awareness and social aspects, groupware design and development, computer supported collaborative learning, groupware applications and studies, group negotiation and knowledge management, and groupware activities and evaluation.