Postmastectomy pain syndrome is a common sequela of breast cancer treatment that can lead to impairments and limited participation in work, recreational, and family roles. Pain can originate from multiple anatomic sites. A detailed evaluation to determine the specific cause or causes of pain will help guide the clinician to successfully manage this pain syndrome. There are many available treatments, but more evidence is needed for the efficacy of rehabilitation, pharmacologic, and nonpharmacologic therapy. There is evidence for some effective treatments to prevent this syndrome, but, here also, more research is needed.