Dengue viruses are endemic in Thailand and Southeast Asian countries. A retrospective study of 175 patients with dengue virus infection admitted at the Department of Pediatrics, Ramathibodi Hospital in 1997 was carried out. Fifteen and 160 patients were clinically diagnosed with dengue fever and dengue hemorrhagic fever (DHF), respectively. DHF was commonly found in patients whose ages ranged from 10 to 14 years. The mean body weight was at the 54th percentile for age. In the management, 10.6% of patients with DHF required blood component therapy which included platelet concentrate (64.7%) in patients who exhibited active bleeding, packed red cells (47%) in patients who exhibited a rapid drop in the hematocrit and fresh frozen plasma (29.4%) in patients with circulatory failure who did not respond to intravenous fluid. The transfusion requirement was significantly correlated with the occurrence of bleeding (p < 0.008) and bleeding in the gastrointestinal tract (p < 0.0001) but not correlated with the number of platelet counts (p = 0.207). As a result, physicians in charge should be aware of the transfusion requirement and communicate this to the blood bank in advance for the preparation of appropriate blood components.