The development of new therapeutics for management of pain is likely to become much more mechanism based, and therefore, we need a more thorough understanding of the different pain development pathways. The afferent fibers of sensory neurons, with their cell bodies in the dorsal root ganglia (DRG), are thought to be key in pain mechanisms. DRG neurons can be prepared from embryonic, postnatal, or adult tissue. Embryonic preparations have the advantage of higher cell yields and greater proportion of neurons, but they are dependent on neurotrophins for the first week of culture. In contrast, dissociated postnatal and adult DRG sensory neurons offer the possibility to study mature neurons that may better resemble the in vivo characteristics of these cells. Here, we describe the dissociation of DRG sensory neurons from postnatal and adult rats. DRG are dissected and dissociated using a prolonged trypsin/collagenase treatment, followed by mechanical separation of the neurons. We have routinely prepared them for electrophysiological studies by the methods outlined in this chapter and describe some of the pitfalls that we have encountered, with hints of how to overcome them.