With gas chromatography, we established a method of determining plasma very long-chain fatty acids (VLCFA). Eight cases with adrenoleukodystrophy (ALD) were confirmed by using plasma VLCFA assay as the diagnostic method. The phenotypes of the 8 patients are as follows: 1. Childhood ALD; 2. Adolescent ALD; 3. Adult cerebral ALD: 4. Adrenomyeloneuropathy; 5. Addison's disease without neurologic involvement; 6. Asymptomatic ALD. We do not agree with Moser's classification of ALD as presymptomatic and asymptomatic, but would suggest to have a subclinical type of ALD.