Selecting good-quality sperm for use in in-vitro fertilization is a key step in assisted reproduction. For many years purely morphological attributes have been used to assess suitability, but increasingly biochemical and molecular biological techniques are now identifying sperm with the best chances of producing viable and healthy embryos. Focusing on modern sperm function testing, this manual provides technical details of commonly used tests and gives an overview of the laboratory techniques used to evaluate sperm samples. Covering a variety of testing methods in detail, from manual and computer-assisted semen analysis to zona pellucida binding assays, and tests assessing sperm DNA damage such as the TUNEL assay. Describing the underlying science, practical advice for performing the tests is given, including tips for optimizing outcomes and trouble-shooting. This is an essential guide for reproductive medicine specialists, clinical andrologists, urologists and gynecologists working with sub-fertile men.