A household cooking appliance, in particular an oven, comprising a cooking chamber defined by a muffle having a flue with a fume outlet at an upper wall of the muffle, and a front door, for opening and closing the cooking chamber, the appliance also comprising: a delivery channel, defined by a duct body that extends above the upper wall of the muffle, the duct body having an outlet of the delivery channel that is substantially at a front region of the appliance, above an upper portion of the door, and having a fume inlet in a lower wall of the duct body, which is in fluid communication with the fume outlet of the muffle and with the delivery channel; a ventilation assembly, operatively associated to the duct body so as to draw in fumes from the fume outlet of the muffle and expel them from the outlet of the delivery channel, the ventilation assembly being in a rear end region of the duct body that is generally opposite to the outlet of the delivery channel; wherein the ventilation assembly comprises a radial fan with a centrifugal impeller thereof within the duct body, the centrifugal impeller being positioned above the fume inlet of the duct body substantially coaxial thereto and to the fume outlet of the muffle in such a way that at least the fumes are drawn in from the fume outlet substantially in the direction of the axis of the impeller and forced in a radial direction into the delivery channel for being expelled from the corresponding outlet; wherein the rear end region of the duct body has a generally rounded peripheral profile so as to form a volute of the radial fan, the duct body preferably having a shape generally tapered towards its rear end region and comprising a lower half-shell and an upper half-shell and wherein inside the duct body, within the boundaries of the delivery channel, a flow-deflector element is provided, configured for rendering the flow forced by the centrifugal impeller into the delivery channel uniform; the appliance being characterized in that the flow-deflector element has two converging side surfaces (35a, 35b), one side surface substantially forming a prolongation of a first generally concave stretch of a side of the duct body and the other side surface substantially forming a prolongation of a second generally concave stretch of the side of the duct body, the flow-deflector element being set up against the side in a generally convex transitional stretch thereof between the first stretch and the second stretch in a position comprised between the centrifugal impeller and the outlet of the delivery channel. a delivery channel, defined by a duct body that extends above the upper wall of the muffle, the duct body having an outlet of the delivery channel that is substantially at a front region of the appliance, above an upper portion of the door, and having a fume inlet in a lower wall of the duct body, which is in fluid communication with the fume outlet of the muffle and with the delivery channel; a ventilation assembly, operatively associated to the duct body so as to draw in fumes from the fume outlet of the muffle and expel them from the outlet of the delivery channel, the ventilation assembly being in a rear end region of the duct body that is generally opposite to the outlet of the delivery channel; wherein the ventilation assembly comprises a radial fan with a centrifugal impeller thereof within the duct body, the centrifugal impeller being positioned above the fume inlet of the duct body substantially coaxial thereto and to the fume outlet of the muffle in such a way that at least the fumes are drawn in from the fume outlet substantially in the direction of the axis of the impeller and forced in a radial direction into the delivery channel for being expelled from the corresponding outlet; wherein the rear end region of the duct body has a generally rounded peripheral profile so as to form a volute of the radial fan, the duct body preferably having a shape generally tapered towards its rear end region and comprising a lower half-shell and an upper half-shell and wherein inside the duct body, within the boundaries of the delivery channel, a flow-deflector element is provided, configured for rendering the flow forced by the centrifugal impeller into the delivery channel uniform; the appliance being characterized in that the flow-deflector element has two converging side surfaces (35a, 35b), one side surface substantially forming a prolongation of a first generally concave stretch of a side of the duct body and the other side surface substantially forming a prolongation of a second generally concave stretch of the side of the duct body, the flow-deflector element being set up against the side in a generally convex transitional stretch thereof between the first stretch and the second stretch in a position comprised between the centrifugal impeller and the outlet of the delivery channel.