Elucidation of meiotic recombination mechanisms in mammals faces many obstacles. Much of our understanding has been built upon studies in the fungi, which have served to guide experimental design in mammalian cells and mice. A clearer picture is now emerging which reveals that many of the general principles of recombination are conserved across this evolutionary divide. A number of genes critical to meiotic recombination in yeast also exist in mammals. Transgenic technologies, in addition to advances in molecular biology, now provide several strategies to investigate the properties and regulation of mammalian recombination. This chapter reviews the current state of knowledge regarding recombination in the mammalian germ line, covering topics such as gene conversion, recombination mechanics, recombination-based genetic mutation, crossing over, and genes involved in meiotic recombination.