This book constitutes the refereed proceedings of the 4th International Workshop on Algorithms in Bioinformatics, WABI 2004, held in Bergen, Norway in September 2004.

The 39 revised full papers presented were carefully reviewed and selected from 117 submissions. Among the topics addressed are all current issues of algorithms in bioinformatics, such as exact and approximate algorithms for genomics, genetics, sequence analysis, gene and signal recognition, alignment, molecular evolution, phylogenetics, structure determination or prediction, gene expression and gene networks, proteomics, functional genomics, and drug design.