Long-chain fatty acids in erythrocyte membrane phospholipids were analyzed in three patients with adrenoleukodystrophy (ALD) and four diseased controls with other neurologic diseases by high performance liquid chromatography (HPLC). HPLC chromatograms showed the increase of a very long-chain fatty acid C26:0 in glycerophospholipids of ALD erythrocyte membranes, which was not so prominent in sphingomyelin. The ratio of C26:0 to C22:0 increased in glycerophospholipids as well as sphingomyelin in ALD. These results suggest that ALD has a generalized abnormal metabolism of very long-chain saturated fatty acids.