One hundred and nine children with myelodysplasia were evaluated and classified according to the level and type of paralysis and its effect on functional ability. Thirty-one per cent of the patients were paralysed at the thoracic level, 26% at the upper lumbar level, 30% at the lower lumbar level and 13% at the sacral level. Fifty-four per cent of these patients demonstrated the classic flaccid paralysis in the lower limbs with normal upper limbs; 9% were flaccid in the lower limbs, but were spastic in the upper; 24% were spastic in the lower limbs; 13% were spastic in the upper and lower limbs. Patients with spastic lower limbs required more orthopaedic procedures, more days in hospital and in casts, and were less likely to walk than those with flaccid paralysis. Patients with spastic upper limbs were less likely to be independent in activities of daily living and were more likely to require special schools than patients with normal upper limbs. In addition to the spinal cord level of the lesion, the degree of spasticity is important in the evaluation, treatment and prognosis of myelodysplastic patients.