A total of 254 cases of synovial cysts of the spine have been reported in the English literature, but only eight have been associated with haemorrhagie. We describe a 55-year-old man with acute radiculopathy resulting from haemorrhage involving a synovial cyst at a lumbar facet joint. Traumatic factors could have caused bleeding around or into the synovial cyst. Treatment by resection of the cyst and evacuation of the haematoma led to complete neurological recovery.