Metachromatic leukodystrophy (MLD) is a neurodegenerative disorder with autosomal recessive inheritance, in which cerebroside sulphate (sulphatide) accumulates in the central and peripheral nervous systems due to a deficiency of arylsulphatase A. This article presents a 2-year-old boy who had occasional shortness of breath, horizontal nystagmus and unstable gait for 3 months prior to the entry. He was admitted to our hospital due to shortness of breath, frequent apnea, generalized hypotonia and conscious disturbance. The lumbar puncture, brain CT scan, serum amino acid analysis, urine organic acid assay and nerve conduction velocity of lower extremities all showed negative findings. The electron microscopic finding of muscle elicited lipid deposition. The auditory brainstem response showed bilateral impairment. The routine EEG revealed diffuse slow waves. The brain MRI showed widespread low signals over the white matter of bilateral frontal and parietotemporal areas of the cerebral hemispheres, as well as the white matter of the bilateral cerebellar hemispheres, and the brain stem in the T1-weighted image corresponding the high signals in T2-weighted image. The blood leukocyte lysosomal enzyme activity test revealed arylsulphatase A deficiency. Rapid progressive neurological deterioration was noted since admission. Unfortunately, the patient expired due to respiratory failure in the final.