Background: Obesity is associated with unfavorable outcomes for infectious diseases. Most researches exploring the association between nutritional status and dengue severity have focused on pediatric populations, with only few studies assessing adult patients. Methods: Adult patients with laboratory-confirmed dengue admitted to a tertiary hospital in southern Taiwan between 2014 and 2015 were enrolled retrospectively. Demographics, comorbidities, clinical presentation, laboratory findings, and outcomes were obtained from case-record forms. Patients were categorized into obese group and nonobese group. The obese group comprised patients with a body mass index of ≥27.5 kg/m2. Results: A total of 1417 hospitalized patients with dengue were evaluated. The mean age was 57.9 years (range: 18–92 years). The obese and nonobese groups comprised 333 (23.5%) and 1084 (76.5%) patients, respectively. The obese group included more patients with hypertension (85%, p