Abstract: An exhaust gas burner reactor which comprises a burner apparatus having a combustor tube which extends axially in a spaced relationship to an exhaust gas conduit. The combustor tube has a first, base end having fuel and air inlets and a mixing chamber therein, and a second combustor end having a combustor chamber and outlets for ejecting burning fuel and air into the exhaust gas conduit. The combustor assembly is oriented so as to locate the burner outlets upstream of the first end so that heated exhaust gas/burner output mixture passes through an exhaust reactor defined between the combustor tube and the exhaust gas conduit. The reactor aids in the combustion of unreacted fuel components in the exhaust gas.