Persistent pain after breast cancer surgery is predominantly a neuropathic pain syndrome affecting 25% to 60% of patients and related to injury of the intercostobrachial nerve, intercostal nerves, and other nerves in the region. Neural blockade can be useful for the identification of nerves involved in neuropathic pain syndromes or to be used as a treatment in its own right. The purpose of this review was to examine the evidence for neural blockade as a potential diagnostic tool or treatment for persistent pain after breast cancer surgery. In this systematic review, we found only 7 studies (n = 135) assessing blocks directed at 3 neural structures-stellate ganglion, paravertebral plexus, and intercostal nerves-but none focusing on the intercostobrachial nerve. The quality of the studies was low and efficacy inconclusive, suggesting a need for well-designed, high-quality studies for this common clinical problem.