The deactivation of Zn-encilite catalyst during the aromatization of n-butane to benzene, toluene, and xylenes (BTX) has been investigated as a function of time on stream. The coke responsible for the deactivation was extracted and analyzed by H-1 NMR, HPLC, and MS. The mode of coking was established on the basis of the carbonaceous compounds responsible for deactivation. These compounds were found to be retained at the channel intersections due to trapping. A small amount of deactivation was observed due to pore-mouth poisoning after 10 h reaction time. From the product inhibition experiments a coking mechanism was proposed. The coke precursor was found to be formed from the intermediate butene rather than from the product BTX. In order words the deactivation occurred parallel with the main reaction. A kinetic model has been presented using the Langmuir-Hinshelwood approach. The kinetic parameters in the rate equations and the activation energies have been determined.