The gene expression pathway begins in the nucleus as a gene receives a cue to transcribe, and typically ends in the cytoplasm with the production of the required protein. The nuclear processes of mRNA transcription and nucleo-cytoplasmic transport are of high importance as they encompass the major control points of gene expression. While it has been possible to study the mRNA life cycle using biochemical and molecular biology approaches, the advent of methods for nucleic acid tagging in vivo, have opened up many possibilities for examining these processes in vivo. In this chapter we describe the methodology required for setting up a live-cell system for monitoring real-time mRNA dynamics in mammalian cells.