An exhaust gas purification system for an internal combustion engine, comprising: an exhaust gas purification apparatus that purifies exhaust gas discharged from the internal combustion engine; a fuel addition apparatus that supplies fuel from upstream of said exhaust gas purification apparatus; a turbocharger including a turbine provided in an exhaust pipe (16,19) upstream of said exhaust gas purification apparatus and a compressor provided at a point in an intake pipe of said internal combustion engine; a high pressure EGR apparatus that recirculates a portion of exhaust gas in the exhaust pipe (16,19) upstream of said turbine into the intake pipe downstream of said compressor; a low pressure EGR apparatus that recirculates a portion of exhaust gas in the exhaust pipe (16,19) downstream of said exhaust gas purification apparatus into the intake pipe upstream of said compressor; control means for controlling the amount of the exhaust gas recirculated by said high pressure EGR apparatus and the amount of the exhaust gas recirculated by said low pressure EGR apparatus to control the amount of the exhaust gas passing through said exhaust gas purification apparatus when fuel is supplied to said exhaust gas purification apparatus from said fuel addition apparatus; and characterized by comprising reduction means for performing a reduction process of reducing NOx or SOx stored in a storage reduction type NOx catalyst provided in said exhaust gas purification apparatus by supplying fuel to said NOx catalyst from said fuel addition apparatus, wherein, in cases where recirculation of exhaust gas is performed by said low pressure EGR apparatus at the time when said reduction process is being performed, said control means control the amount of the exhaust gas recirculated by said high pressure EGR apparatus and the amount of the exhaust gas recirculated by said low pressure EGR apparatus so as to decrease the amount of the exhaust gas passing through said exhaust gas purification apparatus, by decreasing the amount of the exhaust gas recirculated by said low pressure EGR apparatus as compared to when said reduction process is not being performed. an exhaust gas purification apparatus that purifies exhaust gas discharged from the internal combustion engine; a fuel addition apparatus that supplies fuel from upstream of said exhaust gas purification apparatus; a turbocharger including a turbine provided in an exhaust pipe (16,19) upstream of said exhaust gas purification apparatus and a compressor provided at a point in an intake pipe of said internal combustion engine; a high pressure EGR apparatus that recirculates a portion of exhaust gas in the exhaust pipe (16,19) upstream of said turbine into the intake pipe downstream of said compressor; a low pressure EGR apparatus that recirculates a portion of exhaust gas in the exhaust pipe (16,19) downstream of said exhaust gas purification apparatus into the intake pipe upstream of said compressor; control means for controlling the amount of the exhaust gas recirculated by said high pressure EGR apparatus and the amount of the exhaust gas recirculated by said low pressure EGR apparatus to control the amount of the exhaust gas passing through said exhaust gas purification apparatus when fuel is supplied to said exhaust gas purification apparatus from said fuel addition apparatus; and characterized by comprising reduction means for performing a reduction process of reducing NOx or SOx stored in a storage reduction type NOx catalyst provided in said exhaust gas purification apparatus by supplying fuel to said NOx catalyst from said fuel addition apparatus, wherein, in cases where recirculation of exhaust gas is performed by said low pressure EGR apparatus at the time when said reduction process is being performed, said control means control the amount of the exhaust gas recirculated by said high pressure EGR apparatus and the amount of the exhaust gas recirculated by said low pressure EGR apparatus so as to decrease the amount of the exhaust gas passing through said exhaust gas purification apparatus, by decreasing the amount of the exhaust gas recirculated by said low pressure EGR apparatus as compared to when said reduction process is not being performed.