Background and study aim: Dengue fever is one of the commonest viral infections in tropical and subtropical areas and its main burden is related to patient's mortality and cost of hospital admission. Our aim was to study dengue fever patients admitted to a tertiary hospital as regards the predictors of patient's death and prolonged hospital length of stay (HLOS). Patients and methods:This study included 123 patients. They were investigated for demographic, clinical and laboratory data that could predict the mortality and prolonged HLOS cases. Results : Ninety one patients were males (74%) and average age was 30.6 ± 13.8 years. 119 patients (96.7%) improved and 4 patients (3.3%) died in the hospital. Out of the 119 patients, 38 patients (30.9%) were discharged after 5 days. Statistically significant predictors of prolonged HLOS (> 5 days) were leucopenia, INR > 1.25 and Creatine Kinase (CK) serum level > 488 IU/dl. Predictors of patient's death were male, non Saudi patients, age > 41.5 years, and complicated case (ICU admission , CNS hemorrhage and renal and/or liver failure). On multivariate logistic regression analysis; the laboratory independent predictors of death were AST > 610 IU/dl, ALT > 150 IU/dl, PT > 16.65 sec and INR > 1.4. Conclusion : In a tertiary hospital in Makkah, the mortality rate of dengue fever patients was 3.3%.Predictors of patient's death were old age, male, non-Saudi patients, ICU admission, CNS hemorrhage, renal and liver failure and on multivariate logistic regression analysis, laboratory predictors were high serum levels of AST, ALT, PT and INR. About 31% of dengue fever patients needed hospital admission for >5 days and the statistically significant predictors were leucopenia, high INR and high CK serum levels.