This book constitutes the refereed proceedings of the Second International Conference on Integrated Formal Methods, IFM 2000, held in Dagstuhl, Germany in November 2000. The 22 revised full papers presented together with the abstracts of two invited talks were carefully reviewed and selected from 58 submissions. The papers are grouped together in topical sections on linking and extending notations, methodology, foundation of one formalism by another, semantics, and verification and validation.