A 3-year-old girl presented with fever and left-sided neck mass that did not resolve despite antibiotic treatment. Physical examination was normal except lymphadenopathy in the left cervical region. Complete blood count was Hb: 8.01 g/dL, leukocyte count: 4034/mm, platelet count: 286,000/mm. On preoperative period, coagulation studies revealed a prolonged activated partial thromboplastin time (aPTT, 46.1 s [N: 21 to 36]), corrected mixing test for aPTT. The prothrombin time and international normalized ratio were in normal limits. Factor VIII levels, von Willebrand factor antigen, and ristocetin cofactor were normal. After the patient was given fresh frozen plasma, lymph node excision was performed. As a result of pathologic examination, Hodgkin lymphoma was diagnosed as classic type. The patient was instituted ABVD chemotherapy protocol for Hodgkin lymphoma. The aPTT at the sixth day of treatment was within normal limits. Coagulation test abnormalities are extremely rare in Hodgkin lymphoma. To our knowledge, this is the first report of prolonged aPTT in a child with Hodgkin lymphoma.