ACP, the Algebra of Communicating Processes, is an algebraic approach to the study of concurrent processes, initiated by Jan Bergstra and Jan Will em Klop in the early eighties. These proceedings comprise the contributions to ACP94, the first workshop devoted to ACP. The work shop was held at Utrecht University, 16-17 May 1994. These proceedings are meant to provide an overview of current research in the area of ACP. They contain fifteen contributions. The first one is a classical paper on ACP by J.A. Bergstra and J.W. Klop: The Algebra of Recursively Defined Processes and the Algebra of...