This book constitutes the refereed proceedings of the Second Asian Symposium on Programming Languages and Systems, APLAS 2004, held in Taipei, Taiwan in November 2004.

The 26 revised full papers presented together with abstracts of 3 invited talks were carefully reviewed and selected from 97 submissions. Among the topics covered are type theory, program transformation, static analysis, verification, concurrent systems, code generation, programming calculi, functional programming languages, language support, component systems, real-time systems, embedded systems, formal systems design, object-oriented design, Java objects, program optimization .