The focus of the Gordon Conference on the Biology of Post-Transcriptional Gene Regulation will be the control of messenger RNA processing. The conference will emphasize the importance of these processing events in biology and medicine. Alternative RNA processing in metazoans, particularly in mammals, provides individual genes with the capacity to encode multiple products. Perhaps the most frequently encountered form of alternative RNA processing is alternative splicing, which often is tightly regulated in time and space within an organism. Alternative splicing is thought to occur in the primary transcripts of more than half of human genes and may be the most powerful engine of proteome diversity. Other RNA processing events, such as polyadenylation and editing, are also regulated and confer further flexibility to the genome. Later processing events in the life of an RNA, such as transport, localization and stability can be critical in determining the ultimate outcome of gene expression. All of the RNA processing events will be discussed in the context of the evolution of the complex genes of metazoans.