Device for resuscitating victims of cardiorespiratory arrest comprising an insufflated air inlet, an outlet for said insufflated air provided at the lower end of an air conveying tube which is configured to penetrate the throat of the victim through the mouth, at least a first one-way valve interposed between said air inlet and air outlet to allow the flow of air from said inlet to said outlet and prevent the flow of a fluid exhaled by the victim in the opposite direction, the body of said valve including an outlet aperture for the exit of the fluid exhaled by the victim, wherein - the valve is housed inside the air conveying tube, wherein the upper end of said insufflated air conveying tube comprises a portion of tube which is configured for internally housing the body of said valve, - the wall of said portion of tube including at least one outer hole communicating with the aperture of the body of the valve to allow discharging the fluid exhaled by the victim to the outside, said outer hole being located at a height greater than the height of said outlet aperture for the exit of the fluid from the valve, - wherein the insufflated air inlet is provided in a nozzle for contact with the mouth of the resuscitator, said nozzle including coupling means (17, 18) for coupling to the upper end of the air conveying tube, - and wherein the first one-way valve comprises an obturating piston which is associated with a spring for maintaining the piston in an upper position in which said piston keeps the passage of fluid towards the nozzle closed by default, said obturating piston being able to move inside the body of the valve to allow the entry of air in the mentioned valve when the insufflated air pressure exceeds the reaction force of the spring, the body of the valve comprising guides along which said piston moves to a lower position, such that in this lower position the piston is housed in a portion of the body of the valve that widens to allow the passage of air through the cavity left free by the piston, said piston closing the outlet aperture of the body of the valve as it moves along said guides due to the insufflated air pressure. - the valve is housed inside the air conveying tube, wherein the upper end of said insufflated air conveying tube comprises a portion of tube which is configured for internally housing the body of said valve, - the wall of said portion of tube including at least one outer hole communicating with the aperture of the body of the valve to allow discharging the fluid exhaled by the victim to the outside, said outer hole being located at a height greater than the height of said outlet aperture for the exit of the fluid from the valve, - wherein the insufflated air inlet is provided in a nozzle for contact with the mouth of the resuscitator, said nozzle including coupling means (17, 18) for coupling to the upper end of the air conveying tube, - and wherein the first one-way valve comprises an obturating piston which is associated with a spring for maintaining the piston in an upper position in which said piston keeps the passage of fluid towards the nozzle closed by default, said obturating piston being able to move inside the body of the valve to allow the entry of air in the mentioned valve when the insufflated air pressure exceeds the reaction force of the spring, the body of the valve comprising guides along which said piston moves to a lower position, such that in this lower position the piston is housed in a portion of the body of the valve that widens to allow the passage of air through the cavity left free by the piston, said piston closing the outlet aperture of the body of the valve as it moves along said guides due to the insufflated air pressure.