We report for the first time an investigation on the catalytic behavior of protonated clinoptilolite zeolite in propane-SCR-NO_x. The protonated Iranian clinoptilolite zeolite shows a promising performance for NO_x abatement via selective catalytic reduction by propane. Maximum activity (72% conversion of NO_x to N₂) is achieved at 450 °C at a low GHSV of 20,280 h⁻¹. Size dependency of the nitrogen production reaction rate is insignificant for particle sizes equal or smaller than 500 μm. A Hinshelwood–Langmuir type reaction mechanism has been proposed that predicts satisfactorily the NO₂/NO mixture conversion rate in the temperature range of 300–400 °C as a function of NO₂ and NO concentration and reaction temperature for an GHSV in the range of 27,000–30,400 h⁻¹. Kinetic analysis was performed based on the data obtained by an integral reactor system. The activation energy of the surface catalyzed reactions proposed has been calculated in the range of 43–51 kJ mol⁻¹.