A process for the production of 3-deoxy-4-ene steroids of the general formula I ##STR1## is described, in which R.sub.1, R.sub.2 and R.sub.3 mean a hydrogen atom or a methyl group,R.sub.4 represents a lower alkyl group, a phenyl group or a free, esterified or etherified hydroxy group,R.sub.5 symbolizes a hydrogen atom, a vinyl group or the grouping --C.tbd.CR.sub.6 with R.sub.6 meaning a hydrogen atom, an alkyl group with a maximum of 4 carbon atoms or a halogen atom,X represents a methylene group, a fluoromethylene group, an ethylidene group or a vinylidene group,Y and U represent a methylene group or an ethylidene group andZ symbolizes a methylene group, an ethylidene group, a vinylidene group, a chloromethylene group or a hydroxymethylene group and in which the bonds represent three single bonds or one double bond and two single bonds or a conjugated double bond.