The invention relates to a process for preparing 1-octene by reacting 1,3-butadiene with a telogen of the formula H—X—Y—H, where X is O, N, S or P and Y is C, N or Si and X and Y bear, depending on their valence, further substituents, in the presence of a telomerization catalyst to form a telomer of the formula H₂CCH—CH₂—CH₂—CH₂—CHCH—CH₂—X—Y—H, partially hydrogenating the telomer to form a 1-substituted 2-octene of the formula H₃C—CH₂—CH₂—CH₂—CH₂—CHCH—CH₂—X—Y—H and dissociating the 1-substituted 2-octene to give 1-octene.