Background: Dengue fever, a viral illness transmitted by mosquitoes, significantly increases morbidity and mortality rates, and its incidence has risen rapidly globally over the past two decades, posing severe public health challenges. This study aimed to determine the prevalence of dengue fever among patients with clinically suspected acute febrile illness at Kalkaal Hospital in Mogadishu, Somalia. Methods: This retrospective study involved patients who attended outpatient clinics at Kalkaal Hospital in Mogadishu (Somalia) between November 2022 and December 2023 to determine the prevalence of dengue fever among patients with clinically suspected acute febrile illness. Logistic regression data analysis was used. Findings: A total of 199,779 patients attended Kalkaal Hospital outpatient clinics during the study period. Of the 4,507 patients who showed dengue symptoms, 264 (5.9%) were positive. This study showed that patients aged <18 years were three times more likely to have dengue fever when compared with those aged ≥18 years (odds ratio: 3.33, 95% confidence interval: 2.57–4.31, p < 0.001). Conclusion: The study reveals a 6% dengue fever burden among study subjects, with males and those under 18 years old showing higher infection susceptibility. However, this is a single-center study, and future research involving more regions and hospitals may yield more conclusive results. Therefore, we recommend promoting dengue vector control surveillance.