Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of pathologic immune activation, occurring as either a familial disorder or a sporadic condition, in association with a variety of triggers. This article will introduce a neonate with HLH in Iran. We report a case of HLH presenting with respiratory distress and fever, hepatosplenomegaly, jaundice and pancytopenia on the second day of life. Typical clinical and laboratory findings were detected in the neonate. HLH was diagnosed according to HLH-2004 guidelines. In spite of initiating the treatment, the disease did not cure. Post-mortem, extensive hemophagocytosis was found in multiple organs. No specific genetic defect was identified. Since HLH is a potentially lethal childhood illness, early diagnosis of this disorder and commences the therapy is important for pediatricians.