Alternative splicing is a common mechanism for the generation of multiple isoforms of proteins. It can function to expand the proteome of an organism and can serve as a way to turn off gene expression post-transcriptionally. This review focuses on splicing and its regulation in C. elegans. The fully-sequenced C. elegans genome combined with its elegant genetics offers unique advantages for exploring alternative splicing regulation in metazoans. The topics covered in this review include constitutive splicing factors, identification of alternatively spliced genes, examples of alternative splicing in C. elegans, and alternative splicing regulation. Key genes whose regulated alternative splicing are reviewed include let-2, unc-32, unc-52, egl-15 and xol-1. Factors involved in alternative splicing that are discussed include mec-8, smu-1, smu-2, fox-1, exc-7 and unc-75.