One difficulty in studying molecular changes of tumours has been the inability to isolate DNA and RNA from a homogeneous cell population. The combination of several new technologies should help overcome these hurdles. Microdissection is a technique for rapid and easy procurement of a pure cellular subpopulation away from its complex tissue milieu. Laser-assisted microdissection has recently been identified as a quick, simple and effective method by which microdissection of complex tissue specimens can be routinely performed for molecular analysis. With the advent of laser microdissection, cDNA libraries can be developed from pure cells obtained directly from stained neoplastic tissue, and microarrays of thousands of genes can now be used to examine gene expression in microdissected tumour tissue samples. This review will concentrate on the application of different microdissection techniques in the area of cancer research.