The first observation in the world literature of the development of subglottic cysts in the larynx in monochorionic monoamniotic twins is presented. The girls were born prematurely at 34 weeks of gestation, from the first day of life for 7 and 8 days, respectively, were transferred to mechanical ventilation. At the fourth month of life, symptoms of laryngeal stenosis appeared and began to gradually progress, conservative therapy had no effect. The diagnosis of subglottic cysts was established on the basis of fibrolaryngoscopy; after endolaryngeal surgery, breathing returned to normal. This case demonstrates the importance of timely endoscopic examination of the respiratory tract in children with stridor.