LS-SNP is a web tool for genome-wide annotation of human SNPs. The current version, LS-SNP/PDB, provides information useful for identifying amino-acid changing SNPs (nsSNPs) that are most likely to have an impact on biological function. The system is kept up-to-date by an automated, high-throughput build pipeline that systematically maps human nsSNPs onto Protein Data Bank structures and annotates several biologically relevant features, inferred from three-dimensional experimental structures.