The products of the photolysis of two steroidal cyclic a-nitro enones, newly synthesized, were compared with those of the cyclic a-nitro ketones and cyclic enones. Direct irradiation of 2a-nitrocholest-4-en-3-one in protic solvents resulted in an unexpected a-cleavage of the carbonyl group and gave 3-alkoxy-2-nitro-2,3-secocholest-4-en-3-one while irradiation of 4a-nitro-5a-cholest-1-en-3-one gave the parent cholest-1-en-3-one which arose from the removal of the nitro group.