Lipid composition of erythroid and myeloid cells of rabbit bone marrow was studied by thin layer chromatography. The myelocaryocytes contained phospholipids, free and esterified cholesterol, free fatty acids and triglycerides. The main components of the total lipid fraction were phospholipids and triglycerides. The ratio of phospholipids was lower and content of triglycerides and cholesterol esters was higher in myeloid cells, as compared with erythroid cells. Also myeloid components of bone marrow contained 1.8-fold more lipids per one cell than the erythroid cells.