The present subject matter discloses a fluid cooled reformer for gas turbine systems and a method for cooling both a fuel reformer and a heated reformate stream produced by such fuel reformer. The fluid cooled reformer may include a pressure vessel and a reactor assembly disposed within the pressure vessel. The reactor assembly may include a reactor and may be configured to receive and reform an oxygen/fuel mixture to produce a heated reformate stream. Additionally, the fluid cooled reformer may include an inlet configured to direct a fluid stream into the pressure vessel. At least a portion of the fluid stream may be used to cool the reactor assembly. A reformate cooling section may be disposed downstream of the reactor of the reactor assembly and may be configured to cool the heated reformate stream.