Sri Lanka is a south-Asian island of Indian Ocean and situated south-east of the Indian subcontinent. It is in the grip of a severe dengue epidemic. Currently, dengue fever [DF] and dengue hemorrhagic [DHF] fever cases are reported all part of the SriLanka, but we could observe two peaks in absolute number and incidence of DF and DHF occur annually along with monsoon rain and density of two mosquito vector species (Aedes aegypti and Aedes albopictus).In the eastern part of the SriLanka, there were dengue out break started in January 2017.This study was conducted in the Tertiary care hospital Batticaloa, SriLanka. Objectives of the study were to know the pattern of distribution of DF among male and female and to know the incidence of laboratory confirmed dengue cases among clinically suspected dengue patients. During this last four month period number of suspected dengue fever cases increased steadily, from 1st of January 2017 to 31st of April there were 2562 suspected dengue cases admitted in this hospital. Last four months 1811 dengue-IgM and IgG antibodies tests were carried out, only 760(41.96%) cases were positive for primary infection