Pertussis in a young infant is often fatal as it can easily be misdiagnosed and because infants have weak immune systems before they receive routine infant immunization. The so called “whooping cough” can cause respiratory distress, hypoxemia, and disease progression leading to increased morbidity or mortality. Malignant pertussis is characterized by severe respiratory failure, pulmonary hypertension, leucocytosis and death. Herein, we report the case of a 26–day–old male newborn who presented with cough–cold and difficulties in breathing. After admission, her cough worsened and was accompanied by persistent hypoxemia and apneic spells. With worsening clinical condition, seizures were noticed on second day. With provisional diagnosis of Malignant Pertussis, injectable azithromycin was added. Double volume exchange transfusion was performed. Unfortunately, patient died from pulmonary hypertension, intractable seizures and multi–organ failure. We suggest that all pregnant women should receive pertussis vaccinations in the third trimester of pregnancy