We report here the different components of erythrocyte membrane skeleton proteins between acute monocytic leukemic (AMoL) patients and normal people. The bands in the 2 region of ghost membrane from AMoL patients exhibited significant differences on SDS gel electrophoresis. Band 2.2 was found to be missing and a "new" band with molecular weight (MW) 161,000 appeared. Also band 4.9 was missing, and the amounts of spectrin, actin, and band 4.8 of AMoL patients were decreased markedly. No such alterations can be seen in normal individuals, even in acute myeloid leukemic (AML) and chronic myeloid leukemic (CML) patients.