We report a case of an infant who presented at one month of age with severe malnutrition and neonatal cholestasis. He was born at term in Romania where no cystic fibrosis screening was performed. He rapidly developed cirrhosis and portal hypertension associated with severe pulmonary involvement leading to death at six months of age. Cystic fibrosis was diagnosed based on sweat test and genetic exam. Molecular analysis for CFTR gene identified a new undescribed c.1853_1863del deletion and a SERPINA 1 mutation corresponding to PiS phenotype. Concomitantly, we evidenced medium-chain acyl-CoA deficiency (MCAD). To our knowledge, this association was never described and might be responsible for rapid clinical deterioration and early hepatobiliary complications.