In our 19 years’ experience at King Chulalongkorn Memorial Hospital, we were able to observe 21 pediatric cases with anaplastic large cell lymphoma (ALCL). Of these 21 cases, 4 (19% of ALCL cases) had concurrent hemophagocytic lymphohistiocytosis (HLH). All developed fever, lymphadenopathy and exaggerated signs of capillary leakage syndrome such as generalized edema, pleural effusion or ascites. The hyperinflammation was demonstrated with fever, hypoalbuminemia and elevated inflammatory markers. A high index of suspicion is warranted to recognize concurrent HLH when patients develop cytopenia, splenomegaly, liver dysfunction and pleural or pericardial effusions. For HLH with unknown etiology but with lymphadenopathy, lymph node biopsy should be considered as a part of secondary HLH workup to rule out malignant-associated hemophagocytic syndrome. Treatment with lymphoma-directed therapy should not be contraindicated once a diagnosis of ALCL is made. Instead, one should be cautious whenever a hyperinflammatory state and multi-organ dysfunction exists because HLH-sensitive agents such as corticosteroid, etoposide, cyclosporin A, cyclophosphamide, IVIG and others should be urgently administrated. The mortality was quite high (50%) in our institution. Initial treatment with HLH protocol saved the lives of the other 2 patients (50%), both of whom were cured later with lymphoma-directed protocol.