This book constitutes the refereed proceedings of the 8th International Conference on Mathematics of Program Construction, MPC 2006, held in Kuressaare, Estonia in July 2006. The book collects 22 revised full papers presented with 3 invited talks. Issues addressed range from algorithmics to support for program construction in programming languages and systems. Topics of special interest are type systems, program analysis and transformation, programming language semantics, program logics.