A catalyst and process for opening aliphatic cyclic hydrocarbons have been developed. The catalyst comprises a catalytic metal component, a molecular sieve and refractory inorganic oxide component. The molecular sieve is selected from the group consisting of MAPSOs, SAPOs, UZM-8, UZM-8HS, UZM-15, UZM-15HS, UZM-16, UZM-16HS and mixtures thereof. Preferred catalytic metals include platinum, palladium and rhodium. The catalyst may also contain a modifier such as niobium, titanium, or rare earth metals.