Alternative splicing is an important and prevalent mechanism of gene regulation in higher eukaryotes. Nearly three quarters of human multi-exon genes are alternatively spliced. There is great interest in discovering alternative splicing events in the transcriptome of cancer cells, and in understanding how alternative splicing contributes to tumorigenesis. In this article, I will review recent advances in global analyses of pre-mRNA alternative splicing, and the applications of these genomic technologies to studies of alternative splicing in human cancers.