The chromyl chloride oxidations of cyclohexene and 1-methylcyclohexene have been reexamined. The products from cyclohexene were found to be cyclohexanone,cis- andtrans-2-chlorocyclohexanols, 2-chlorocyclohexanone, cyclohex-2-enol, cyclohex-2-enone, and cyclohexene oxide. Treatment of cyclohexene oxide with chromyl chloride produced onlytrans-2-chlorocyclohexanol and 2-chlorocyclohexanone. The products from 1-methylcyclohexene were 2-methylcyclohexanone, 1-methylcyclopentyladehyde,cis- andtrans-2-methyl-2-chlorocyclohexanol, 2-methyl-2-chlorocyclohexanone, 2-methylcyclohex-2-enone, and 4-methylcyclohex-2-enone. Treatment of 2-methylcyclohexene oxide with chromyl chloride yielded only 2-methylcyclohexanone and 1-methylcyclopentylaldehyde. The origin of the various products and possible mechanisms for their formation is discussed. A 1,3-cyclic addition reaction is proposed for the formation of thecis-chlorohydrins.