Dehydrogenation of propane was carried out on several promoted Pt catalysts. The performance of the catalysts (activity, selectivity and coke formation) was compared in steam and hydrogen environment. Promoting Pt supported on theta -alumina with Sn and K is essential for developing high-performance catalysts. The combination of optimal catalyst composition and steam yields high activity and selectivity at low coke formation. Inferior results were measured with hydrogen as diluent. Characterization of catalysts using XPS, TEM and chemisorption methods supported the results of reaction data.