The present invention relates to an ammonia oxidation catalyst for the treatment of an exhaust gas stream, the catalyst comprising a coating disposed on a substrate, wherein the coating comprises a selective catalytic reduction component being a zeolitic material comprising one or more of copper and iron; and an oxidation catalytic component comprising platinum supported on a porous non-zeolitic oxidic support, wherein the oxidation catalytic component further comprises a first oxidic material supported on the porous non-zeolitic oxidic support supporting platinum, wherein the first oxidic material comprises titania.