In this chapter, we establish a theoretical framework for the rare manifestation of synaesthesia for pain; that is, the sensation in one part of the body (pain) produced by stimulus (pain) observed or imagined in another. We first describe mirror neuron systems (MNS) and the implications these systems have on imitation, behavioral mimicry, communication, socialization, and empathy. Behavioral and emotional contagion may signify disinhibition of behavioral mirroring that is closest to synaesthesia for pain. We describe cases of synaesthesia for pain, including one case of mirrored pain with hyperalgesia, eight cases of mirrored pain in a phantom limb following amputation, one case of mirrored pain in the stump following amputation, and one case of mirrored pain following traumatic childbirth. We then explore the mechanisms that may underlie the experience of pain when observing, or even thinking about, another in pain, including mirror neurons, empathy, and motor systems, the Autonomic Nervous System and visceral mechanisms, and the potential role of sensitization to pain and hypervigilance to pain cues. We conclude that synaesthesia for pain is most likely a consequence of disinhibited activation, or central sensitization, of a fundamentally adaptive system for the empathic perception of pain in another.