The effect of the incorporation of bentonite (BT) untreated and treated with octadecylamine on the rheological behavior and vulcanization kinetics of NBR was investigated. Mechanical properties were also evaluated. Decreases in the optimum cure time (t(90)) and in the scorch time (t(S2)) and a notorious improvement in mechanical properties were found when treated BT was employed. From the vulcanization kinetics analysis, we can infer that the curing rate is superior for the treated BT composites, while the reaction orders point out the dependency of the vulcanization reaction on the initial reactants if compared to the catalytic effect of the reaction products.