The clinical course of 21 patients who underwent syringopleural shunting for syringomyelia is summarised. All the patients were continuing to deteriorate at the time of the operation. Objective improvement was seen in nine patients following the procedure but three subsequently deteriorated. Contralateral syrinx symptoms have appeared in two patients. No change was seen in six patients who did not deteriorate later. Three were worse following the procedure.In syringomyelia with marked hydrocephalus, ventricular drainage by a valved shunt may be the preferred first procedure. Craniovertebral decompression is recommended for syringomyelia with hindbrain herniation without dense arachnoiditis. In appropriate cases syringopleural shunting may be performed in combination with craniovertebral decompression, and may be the procedure of choice in cases with marked hindbrain arachnoiditis. In cases with a sizeable syrinx who have subsequently deteriorated following craniovertebral decompression, syringopleural shunting may be considered the preferred second procedure. Syringopleural shunting is suggested in amenable cases of syringomyelia associated with spinal tumour, trauma or arachnoiditis.