This volume contains all the papers presented at the Fourth International Workshop on Analogical and Inductive Inference (AII'94) and the Fifth International Workshop on Algorithmic Learning Theory (ALT'94) which were held October 10-11, 1994, and October 13-15, 1994, respectively, at Reinhardsbrunn Castle, Germany. This twin conference was motivated by our efforts to concentrate research work in the area called algorithmic or computational learning theory, and by the intention to extend and intensify the communication within the relevant scientific community. The series of workshops on Analogical and Inductive Inference, which established in 1986 (cf. Lecture Notes in Computer Science