Dengue is one of the most important viral diseases especially in the tropical regions. According to the WHO almost 50 million people get dengue infection annually and WHO estimates almost half of the world’s population lives in countries having endemicity for dengue infection. Most common clinical presentation of Dengue fever (DF) is of an acute febrile viral disease with headaches, bone, joint and muscular pains, rash and leucopenia. It is also known as break bone fever due to the severe bone pains. Dengue hemorrhagic fever (DHF) is characterized by four major clinical manifestations: high grade fever, hemorrhagic phenomena, often with hepatomegaly and, in severe cases, signs of circulatory failure. Severe plasma leakage in these patients can lead to hypovolemic shock and circulatory failure. This is called dengue shock syndrome (DSS) and can lead to death. Hence based on above findings the present study was planned to evaluate the Clinical Assessment of Dengue Fever with Respect to Haematological Profile in Pediatric Cases from Bihar Region. The present study has been done in Department of Pediatrics, Darbhanga Medical College and Hospital, Laheriasarai, Darbhanga, Bihar, India. Total 30 cases of the dengue were enrolled in the present study. All the routine investigations like complete blood count (haematology auto-analyser, sysmax xs800i), peripheral blood film for cell morphology, thick and thin blood smear for malaria parasite, specific malarial antigen card test, random blood sugar, complete urine examination, were done. Dengue IgM and IgG by ELISA was done in all the cases. In a few cases chest X-ray PA view, liver function tests, renal function tests and ultrasonography of abdomen were also done. From the present study it can be concluded that dengue fever is a viral infection caused by transmission of the virus through mosquitoes, and accurate physical examination and proper follow-up of haematological changes are needed to decrease morbidity and mortality among children.