Background: Dengue fever is a quickly emerging arboviral infection spread by Aedes aegypti mosquitoes with major public health consequences for millions of people around the world, particularly in rural South-East Asia and Asia-Pacific, according to the World Health Organization. Objectives: To study the clinical presentations and laboratory findings of dengue and dengue hemorrhagic fever during the October to December 2011 outbreak in Islamabad / Rawalpindi, Pakistan. Methods: We sampled 220 patients aged 14 years and above with confirmed dengue fever, presented in the outpatient and emergency department at Capital Development Hospital, Islamabad from October to December 2011. All patients were inlucded in the survery during a dengue outbreak in Islamabad and Rawalpindi area, and were studied for clinical and laboratory findings of dengue and dengue hemorrhagic fever. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS, Version 13.0). Results: The most common symptoms were fever (100%), myalgia (100%), vomiting (86%), skin rash (53.7%), joint pain (20%), retro-orbital pain (18%), and headaches (13%). Moreover, in 10% of cases bleeding (epistaxis, melena and hematemesis) occurred. Routine laboratory findings were leucopenia (100%), thrombocytopenia (100%), proteinuria (96%), raised ALT (60%), AST (40%) and ECG changes (2.5%). The diagnosis was confirmed by ELISA detection of dengue virus immunoglobulin M antibodies. Conclusion: High grade fever with myalgia, leucopenia and thrombocytopenia were characteristic features of dengue fever, and additionally, hemorrhagic manifestations indicated dengue hemorrhagic fever.