We report an association between an extraforaminal disc herniation at the L5-S1 level causing an L5 radiculopathy and a reflex sympathetic dystrophy (RSD) in the affected foot. This is only the second reported case of a disc herniation at this level causing an RSD syndrome. We opted to treat both problems through a retroperitoneal approach involving a discectomy and a surgical sympathectomy. There was immediate and lasting relief from all symptoms, which has been maintained at 18 months' follow-up. The possible mechanisms for this condition are discussed as well as the various treatment options.