Chemotaxis is a fascinating biological process, through which a cell migrates along a shallow chemoattractant gradient that is less than 5% difference between the anterior and posterior of the cell. Chemotaxis is composed of two independent, but interrelated processes--motility and directionality--both of which are regulated by extracellular stimuli and chemoattractants; small GTPases have been shown to be involved. In this chapter, the methods that are used to prepare mouse neutrophils and study their chemotactic behaviors and morphological and biochemical changes in response to chemoattractant stimulation are described.