Photochemical rearrangement of 6-nitrocholesteryl acetate in ethanol is shown to give as the major product 3-oximinocholest-4-en-6-one. The same oxime is obtained from 3β-chloro-6-nitrocholest-5-ene but not from 6-nitrocholesterol on irradiation in ethanol. The photochemically-induced rearrangement of 6-nitrocholesteryl acetate in cyclohexane is also reported.