Complex regional pain syndrome (CRPS) may develop after limb trauma and is characterized by pain, sensory-motor and autonomic symptoms. Most important for the understanding of the pathophysiology of CRPS are recent results of neurophysiological research. Major mechanism for CRPS symptoms, which might be present subsequently or in parallel during the course of CRPS, are trauma-related cytokine release, exaggerated neurogenic inflammation, sympathetically maintained pain and cortical reorganisation in response to chronic pain (neuroplasticity). The recognition of these mechanisms in individual CRPS patients is the prerequisite for a mechanism-oriented treatment.