Neonates have never been reported to be symptomatic when affected with a low affinity β-globin variants. We describe here an isolated cyanosis in a full-term neonate who inherited Hb Saint Mandé variant from his father. He exhibited a low oxygen saturation with no sign of pulmonary disease since birth. The risk for the hemoglobinopathy was known but the medical staff initially supposed that there was no reason for clinical impact because of high proportion of HbF. Pediatricians may be aware of the possibility of such conditions to avoid unnecessary investigations and treatment, even in the first days of life.