The  incidence of dengue fever increase annually and can increase morbidity and mortality. Dengue fever is mosquito-borne disease and caused by one of four serotype dengue viruses. Severe dengue is characterized either by plasma leakage, fluid accumulation, respiratory distress, severe bleeding, or organ impairment. Mortality and serious morbidity of dengue were caused by several factors including the late recognition of the disease and the changing of clinical signs and symptoms. Understanding the prognostic factors in severe dengue will give early warning to physician thus decreasing the morbidity and mortality, and also improving the treatment and disease management. The aim of this study was to analyze the prognostic factors of severe dengue infection in children. This study was observational cohort study in children (2 months-18 years) with dengue infection according to WHO 2009 criteria which admitted in  Soetomo and Soewandhie Hospital Surabaya. Analysis with univariate, bivariate and multivariate with IBM SPSS Statistic 17. All patients were confirmed by serologic marker (NS-1 or IgM/IgG Dengue). Clinical and laboratory examination such as complete blood count, aspartate aminotrasnferase (AST), alanine aminotrasferase (ALT), albumin, and both partial trombocite time and activated partial trombosit time (PTT and aPPT) were analyzed comparing nonsevere dengue and severe dengue patients. There were 40 subjects innonsevere and 27 subjects with severe dengue infection. On bivariate analysis, there were significant differences of nutritional status, abdominal pain, petechiae, pleural effusion, leukopenia, thrombocytopenia, hypoalbuminemia, history of transfusion, increasing AST>3x, prolonged PPT and APTT between severe and nonsevere dengue group. After multivariate analyzed, the prognostic factors of severe dengue were overweight/obesity (p=0.003, RR 94), vomiting (p=0.02, RR 13.3), hepatomegaly (p=0.01, RR=69.4), and prolonged APTT (p=0.005, RR=43.25). In conclusion, overweight/obesity, vomiting, hepatomegaly, and prolonged APTT were prognostic factors in severe dengue infection in children.Those factors should be monitored closely in order to reduce the mortality and serious morbidity.