The gas phase thermal decomposition of 1-bromo-3-chloropropane in the presence of radical inhibitor was studied by using the conventional static system. The mechanism of unimolecular elimination channel is shown below. [...] In this scheme, the total molecular dissociation rate constant, ($k_1;+;k_2$), for the decomposition of $BrCH_2CH_2CH_2Cl$ was determined by pyrolyzing the $BrCH_2CH_2CH_2Cl$ in the temperature range of $380-420^{circ}C$ and in the pressure range of 10∼100 torr. To obtain $k_3;and;k_4,;and;to;obtain;k_1;and;k_2$ independently, the thermal decompositions of allyl chloride and allyl bromide were also studied. The Arrhenius parameters for each step are as follows; $log;A_{infty};=;14.20(sec^{-1}),;E_a$ = 56.10(kcal/mol) for reaction path 1; $log;A_{infty};=;12.54(sec^{-1}),;E_a$ = 49.75(kcal/mol) for reaction path 2; $log;A_{infty};=;13.41(sec^{-1}),;E_a$ = 50.04(kcal/mol) for reaction path 3; $log;A_{infty};=;12.43(sec^{-1}),;E_a$ = 52.78(kcal/mol) for reaction path 4; Finally, the experimentally observed pressure dependence of the rate constants in each step is compared with the theoretically predicted values that are obtained by the RRKM calculations.