Abstract The in vivo incorporation of acetate-2- 14C into cholesterol and fatty acid of tissues of dystrophic mice and their littermate controls was determined. The greatest active incorporation of the acetate is observed with liver followed by kidney, muscle, and brain. Comparison of the radioactivites in the whole tissue and the perchloric-acid-soluble fraction for dystrophic mice with those for the controls showed no appreciable differences. When the mice were not starved, both the specific activities and the relative activities (specific activity of dystrophic tissue divided by specific activity of control tissue) of cholesterol and fatty acid were significanctly reduced in liver, kidney, and muscle of the dystrophic animals. Brain and kidney of starved mice showed a reduced relative activity in cholesterol and fatty acid. No changes were observed in liver and muscle. Incorporation into cholesterol and fatty acid, on a whole muscle basis, is in general reduced for dystrophic muscle. Under the conditions studied ( in vivo incorporation for 1 hour into tissues of starved and nonstarved animals), the results obtained do not provide evidence of an enhanced incorporation of acetate-2- 14C into cholesterol and fatty acids in dystrophic muscle.