A thermostat for gas cooking appliances, comprising a body provided with an inlet fluidically connectable to a gas feed source and with at least a first exit conduit and a second exit conduit, and characterised by comprising, inside said body: - a first chamber positioned in fluidic communication with said gas inlet and provided with a main outlet aperture, - a cavity housing a safety valve, said cavity being fluidically interposed between said gas inlet and said first chamber, - a second chamber positioned downstream of said first chamber and provided with an inlet aperture in fluidic communication with said main outlet aperture of said first chamber, - a valve housed in said first chamber and provided with a slider axially movable within this latter between a first position in which said main outlet aperture is closed, and a second position in which this latter is totally open, - a temperature sensitive element mechanically associated with said valve to cause it to undergo its axial movements on the basis of the temperature measured by a bulb applicable to said cooking appliance and against the elastic reaction of elastic means acting in the sense of urging said valve towards said open position, - means (38, 40, 45) for modifying the position of the slider of said valve relative to the aperture of said main outlet of said first chamber to hence regulate the gas stream which leaves said first chamber via the aperture of said main outlet, and enters said second chamber via said inlet aperture, - a distributor housed within said second chamber and movable between a first position, in which said inlet aperture of said second chamber communicates with said first exit conduit but not with said second exit conduit, and a second position, at which said inlet aperture of said second chamber communicates with said second exit conduit but not with said first exit conduit, - means (38, 34, 76) for moving said distributor between said first position and said second position, - at least one circuit (63, 64, 65; 68, 70, 72, 67, 69) which, by bypassing said second chamber, puts said first chamber into fluidic communication with a region of one of said exit conduits (24, 26) positioned downstream of said distributor, wherein said means (40, 45) for modifying the position of the slider of said valve and said means (34, 76) for moving said distributor are implemented by the same control member. - a first chamber positioned in fluidic communication with said gas inlet and provided with a main outlet aperture, - a cavity housing a safety valve, said cavity being fluidically interposed between said gas inlet and said first chamber, - a second chamber positioned downstream of said first chamber and provided with an inlet aperture in fluidic communication with said main outlet aperture of said first chamber, - a valve housed in said first chamber and provided with a slider axially movable within this latter between a first position in which said main outlet aperture is closed, and a second position in which this latter is totally open, - a temperature sensitive element mechanically associated with said valve to cause it to undergo its axial movements on the basis of the temperature measured by a bulb applicable to said cooking appliance and against the elastic reaction of elastic means acting in the sense of urging said valve towards said open position, - means (38, 40, 45) for modifying the position of the slider of said valve relative to the aperture of said main outlet of said first chamber to hence regulate the gas stream which leaves said first chamber via the aperture of said main outlet, and enters said second chamber via said inlet aperture, - a distributor housed within said second chamber and movable between a first position, in which said inlet aperture of said second chamber communicates with said first exit conduit but not with said second exit conduit, and a second position, at which said inlet aperture of said second chamber communicates with said second exit conduit but not with said first exit conduit, - means (38, 34, 76) for moving said distributor between said first position and said second position, - at least one circuit (63, 64, 65; 68, 70, 72, 67, 69) which, by bypassing said second chamber, puts said first chamber into fluidic communication with a region of one of said exit conduits (24, 26) positioned downstream of said distributor,