Distraction osteogenesis (DO) has been one of the most innovative concepts in cranio-maxillofacial syndromology and surgery over the last 25 years.Early mandibular distraction in severe micrognathia has recently been recognized as an effective treatment option to safely relieve upper airway obstruction associated with mandibular deficiency.An increased incidence in temporomandibular joint complications during DO in neonates has recently been reported, especially in syndromic patients.The authors report 2 children affected by severe micrognathia and severe respiratory distress at birth.Early DO was performed during the first 2 months of the life in another institution with the aim of increasing mandibular length and upper airway size.Both the patients had severe restricted jaw opening after DO and mandibular abnormalities.Temporomandibular joint ankylosis after early mandibular distraction could be a considered a new pathological entity.