A process for preparing 1-butene, which includes nonoxidatively, catalytically dehydrogenating n-butane to obtain a product gas stream of n-butane, 1-butene, 2-butene, butadiene, hydrogen, and secondary constituents; removing hydrogen and the secondary constituents to obtain a C.sub.4 product gas stream; separating the C.sub.4 product stream into a recycle stream of n-butane and a stream of 1-butene, 2-butene and butadiene by extractive distillation, and recirculating the recycle stream to the dehydrogenation zone; introducing the 1 -butene, 2-butene and butadiene stream into a selective hydrogenation zone and selective hydrogenation of butadiene to 1-butene and/or 2-butene to obtain a stream of 1-butene and 2-butene; introducing the 1-butene and 2-butene stream, and a circulating stream of 1-butene and 2-butene into a distillation zone and isolation of a product stream; and introducing the 2-butene-containing stream into an isomerization zone to obtain a circulating stream of 1-butene and 2-butene, and recirculating the circulating stream to the distillation zone.