The gas tube fryer comprises substantially 90° in-shot burners, burner mounting boxes, a one-piece burner mounting bracket, and a bracket housing, all of which are used in conjunction with heat exchanger tubes, heat transfer baffles, a frypot, and a flue in a fryer. The burner mounting boxes are keyed specifically to the face of the burner, preventing substantial movement of the burners and introduction of ambient air into the heat exchange tubes. Each burner is also keyed to the mounting bracket, also preventing substantial movement and providing easy installation and repair. The ninety-degree orientation of the burners facilitates mixing of the combustion gases, and the burner comprises a screen on its face that helps to ensure maximum burner efficiency.