Monochlorinated hydrocarbons of high isomeric purity are prepared by a process, which comprises: reacting a monoalcohol having an alkyl radical having from 3 to 20 carbon atoms with cyanuric chloride; and purifying the resulting monochlorinated hydrocarbon by distillation after separation of salts and washing the monochlorinated hydrocarbon with alkali. The invention relates to a process for preparing monochlorinated hydrocarbons which contain an alkyl radical having from 3 to 20 carbon atoms and have a high isomeric purity by reacting a monoalcohol having a hydrocarbon radical containing an alkyl radical having from 3 to 20 carbon atoms to which additional cycloaliphatic radicals, aryl radicals, aralkyl radicals and alkylaryl radicals may be bound with cyanuric chloride, separating off salts, washing the reaction mixture with alkali and purifying the resulting monochlorinated hydrocarbons by distillation.