This volume constitutes the proceedings of the 4th International Conference on Algebraic Methodology and Software Technology, held in Montreal, Canada in July 1995. It includes full papers or extended abstracts of the invited talks, refereed selected contributions, and research prototype tools. The invited speakers are David Gries, Jeanette Wing, Dan Craigen, Ted Ralston, Ewa Orlowska, Krzysztof Apt, Joseph Goguen, and Rohit Parikh. The 29 refereed papers presented were selected from some 100 submissions; they are organized in sections on algebraic and logical foundations, concurrent and reactive systems, software technology, logic programming and databases.