Cooled transition duct for a gas turbine engine

24A transition duct for a gas turbine engine having improved cooling and reduced stress levels. The transition duct may be formed of two panels (() joined together with welds disposed remote from the bent corner regions of the panels. Cooling channels extending longitudinally in the direction of flow of the hot combustion gas carried by the duct are formed within each panel, including the corner regions. Because the entire annular width (W) of the transition duct is cooled, the gap (G) separating adjacent ducts around the inlet to the turbine may be reduced when compared to prior art designs. Two-panel construction with welds remote from the corner regions is facilitated by maintaining the minimum bend radius in the corners (R) and in the direction of flow (R) to be greater than in prior art designs.