We report a case of self-decapitation by suicidal hanging from a river bridge and discuss the decapitation mechanism, reviewing the literature. The torso and the head of the victim, respectively, were found apart in a river approximately 100 m and 600 m, respectively, downstream from the bridge in two days. Morphological, serological and DNA analyses confirmed their identity. Torn ligaments between the atlas and axis accompanied by fractures in the axis at the partes interarticulares were indicative of a traction force combined with anteroflexion of the head by falling from a height, and the radial pressure due to a strong, single twisted nylon rope with a slip knot was considered to have contributed considerably to the subsequent skin laceration with wavy marginal abrasions. In the reviewed literature, cervical spine fractures were described only in two of six cases, suggesting head movement at the time of decapitation.