Two patients who postoperatively developed extensive multiseptated hydrosyringomyelia following surgical repair of a lumbal meningomyelocele are reported. Since MRI has been available, an increasing number of reports showed that MRI is useful in the diagnosis of hydrosyringomyelia. Hydrosyringomyelia can be considered as a dysraphic lesion. Etiology and pathogenesis of hydrosyringomyelia are still not fully understood. Probably arachnoidal adhesions and cord tethering in both patients may be potential factors in producing cystic degeneration of the underlying structure secondary to ischemia.