Disclosed is a method for the oligomerization of olefins, wherein an olefin is brought into contact with a catalyst system that is obtained from a chromium source, a cycloalkylalkyl-substituted triazacyclohexane, especially a 1,3,5-tris-(cycloalkylalkyl)-1,3,5-triazacyclohexane and an activator such as an alkyl aluminum compound or an alkylalumoxane.