A process for preparing branched olefins comprising 0.5% or less quaternary aliphatic carbon atoms, which process comprises dehydrogenating an isoparaffinic composition over a suitable catalyst which isoparaffinic composition comprises paraffins having a carbon number in the range of from 7 to 35, of which paraffins at least a portion of the molecules is branched, the average number of branches per paraffin molecule being at least 0.7 and the branching comprising methyl and optionally ethyl branches, and which isoparaffinic composition may be obtained by hydrocracking and hydroisomerization of a paraffinic wax; a method of using olefins for making an anionic surfactant, a nonionic surfactant or a cationic surfactant, in particular a surfactant sulfate or sulfonate, comprising converting the branched olefins into the surfactant; and an anionic surfactant, a nonionic surfactant or a cationic surfactant which is obtainable by the method of use.