⊿(4)-Cholestenone-4-C(14) metabolism in male Wister rat was studied. ⊿(4)-Cholestenone was not esterified, was metabolized to cholestanone, and then cholestanol. This passway was investigated on thin layer chromatography and radioautogram. In tumor-bearing rat, the metabolism observed about 1.8 times than that of normal, and cholestanone was metabolized 1.5 times greater than in normal.