It has been found that the joint conversion of butane and hexane over alumina-platinum catalysts opens up a new route of butane conversion yielding C(4+) hydrocarbons with an increased yield of the C(6+) products on a converted hexane basis. It has been shown that a necessary condition for the occurrence of this reaction is the presence of finely divided platinum in the ionic form (Pt(sigma)) in the catalysts. The results of catalytic testing of the samples modified with Cl(-)and F(-) anions allowed a possible mechanism and the nature of active sites of the reaction of the joint conversion of butane and hexane to be proposed.