Juvenile dermatomyositis (JDM) is one of the pediatric systemic connective tissue disorders, consisting of an idiopathic inflammatory myopathy, affecting primarily skin and muscle, representing approximately 85% of cases in this group. A significant source of morbidity is the occurrence of overlap characteristics with other connective tissue disorders, including systemic sclerosis (SSc). Overlap JDM/SSc syndrome is rare in children, with only a few reported cases. The diagnosis is often challenging, presence of anti-PM/Scl antibodies playing a pivotal role. Although SSc/JDM overlap syndrome has less frequent visceral involvement, pulmonary dysfunction may occur. The respiratory function evaluation using overnight cardiorespiratory polygraphy may reveal important alveolar hypoventilation with impact on therapeutic approach. Non-invasive ventilation may be indicated to potentiate medical treatment. In the acute phase, non-invasive ventilation is a life-saving therapeutic option until the maximum efficiency of drug treatment is reached. In the case of a complex respiratory pathology, associating elements of nocturnal alveolar hypoventilation specific to neuromuscular disease, with that of chronic interstitial lung disease, the evaluation of respiratory sleep disorders should be considered, sometimes requiring home nocturnal noninvasive ventilatory support. We present the case of a 15-year-old girl who was admitted to our clinic with a history of high fever, productive cough and severe dyspnea. Detailed anamnesis revealed that the patient accused oneyear history of proximal muscle weakness of the lower limbs, with functional limitations, weight loss, dysphonia, swallowing difficulties and dyspnea at minimal efforts. Following the physical examination, laboratory and imagistic investigations were all suggestive for an inflammatory myopathy. Anti-PM/Scl antibodies were positive, confirming the diagnosis of a severe form of JDM/SSc overlap syndrome, with minimal cutaneous changes, significant muscle involvement and respiratory distress. Complex therapy using antimicrobial agents, steroid pulse therapy, immunosuppressive agents, non-invasive ventilation, masticaoxygen supplementation and physiotherapy was started, with significant status improvement. However, pulmonary function tests maintained severe restrictive aspect and nocturnal cardio-pulmonary polygraphy revealed residual pulmonary failure with important nocturnal alveolar hypoventilation. Nocturnal non-invasive ventilation was continued at home, along with medical treatment. Her disease was clinically well controlled, immunosuppressive therapy was decreased and interruption of ventilatory support was possible at six months after the diagnosis.