The use of the laryngeal mask airway, a new form of airway, is described in infants and young children receiving radiotherapy under general anesthesia. The laryngeal mask airway consists of a tube, at the distal end of which is attached an elliptically shaped cuff resembling a miniature face mask. The laryngeal mask is inserted blindly into the pharynx, and its cuff forms a low pressure seal around the larynx through which the patient can breathe spontaneously. No complications occurred during use of the laryngeal mask in 25 children who received 312 anesthetics. This experience suggests that the laryngeal mask airway has a valuable role in this situation and may contribute to the safety of anesthesia.