1. Sea-blue histiocytes are seen in a number of clinical conditions. In our patient it appeared to be the result of storage of ceroid-lipofuscin material. 2. Sea-blue histiocytes were present in this patient with a clinical pattern of posterior column dysfunction. Untreated she had low serum vitamin E level but normal oral vitamin E uptake. 3 . The clinical picture could result from neuroaxonal dystrophy of the axons within the cuneate and gracile nuclei or from accumulation of ceroid-lipofuscin material in this area. 4. Large doses of oral vitamin E resulted in normal serum levels but did not appear to alter the stores' of ceroid-lipofuscin in bone marrow or liver.