We evaluated the differences in demographic, clinical, and laboratory findings between adult and pediatric patients hospitalized with dengue fever. Ninety patients with dengue infection admitted at San Lazaro Hospital (SLH), Manila from September 2005 to January 2006 were included in the study. The cases were laboratory-confirmed to have dengue infection. The majority of dengue cases (92%) had secondary dengue infection (median age = 18, age range: 2-37) while the remainder (8%) had a primary dengue infection (median age = 12, age range: 7-22). Nearly all the patients (99%) had dengue hemorrhagic fever (DHF). Sixty-five of the cases (72%) had serotype data: 2 (3%) were dengue virus serotype 1 (DENV-1) (median age = 17), 12 (18%) had DENV-2 (median age = 17.5), 38 (59%) had DENV-3 (median age = 16) and 13 (20%) had DENV-4 (median age = 18). The initial signs, symptoms and laboratory results except hematocrit (p = 0.02) and hemoglobin (p = 0.02) did not differ significantly between adults and children. During the study period, half the cases were adults (218 years; n = 45) and half were children (<18 years; n = 45). The ages of cases ranged from 2 to 37 years (median = 17 years) and the peak incidence was 15-19 years. Dengue is often considered as a pediatric disease. Additional studies are needed to determine if an age shift is occurring and where.