Changes in lipids (cholesterol and phospholipids) of the erythrocyte membrane were studied and several laboratory examinations were performed with 25 male workers employed in a scrap lead refining factory using as controls 38 male railway construction workers. The examinations included measurements of erythrocyte count, hematocrit, mean corpuscular volume (MCV), blood and urine lead concentrations, urine coproporphyrin and delta-aminolevulinic acid, membrane cholesterol (CHO) and phospholipids (PL), total and free CHO in plasma, and lecithin cholesterol acyltransferase (LCAT) activity in plasma. The results were: 1) Membrane CHO (P less than 0.01) and CHO: PL ratio (P less than 0.05) of lead workers were higher than those of the controls. But no significant difference was observed in membrane PL between both groups. 2) Membrane phosphatidyl choline was higher (P less than 0.05) and lysophosphatidyl choline was lower (P less than 0.05) in lead workers compared with controls. But no significant difference was observed in membrane sphingomyelin, phosphatidyl serine, and phosphatidyl ethanolamine between both groups. 3) Free CHO in plasma was higher (P less than 0.05) in lead workers compared with controls. But no significant difference was observed in total CHO in plasma, erythrocyte count, hematocrit, MCV, and LCAT activity between both groups.