The field of biotechnology owes a great deal to the ability to produce recombinant proteins, which can be made in far greater abundance than many native proteins, and are more easily quality controlled. There is a great need for individual proteins to be produced for research purposes. This review is aimed at researchers who are not experienced at protein expression, but find that they have a need to produce a recombinant protein. We detail the major expression systems that will be commonly used in the laboratory situation- bacterial, yeast and insect cell culture. The application of each, and the relative advantages/disadvantages are discussed.