Zeolites with gallium cations on extra-framework positions are interesting catalysts, e.g., in the conversion of methylcyclohexane to a synthetic steamcracker feed consisting mainly of light n-alkanes. Due to the bulky hydration shell of Ga3+ cations, solid-state ion exchange instead of ion exchange in aqueous suspension has to be used to introduce gallium cations into the pore system of medium-pore zeolites. In this work, the solid-state reaction of acidic zeolites with elemental gallium is presented as an alternative route towards Ga-containing catalysts. Upon heating physical H-zeolite/Ga mixtures under water exclusion, two maxima in the rate of evolution of hydrogen were observed. These were assigned to different Ga oxidation states, i.e., +I and +III. After stopping the reaction at ca. 550 degreesC, the obtained Ga+-containing zeolites are sensitive towards water and undergo disproportionation reactions upon contact with humid air. For comparison, a Zn-containing zeolite was also investigated.