Objective: To describe the symptoms of dengue at acute and post-infection stage and to identify preventive strategies adopted by the patients in the Western Province, Sri Lanka. Methods: This was a descriptive cross-sectional study conducted in the Western Province of Sri Lanka in November 2017. The study population consisted of 473 confirmed dengue patients aged from 18 to 64 years who were hospitalized between June and August 2017. A stratified random sampling technique was applied to select the participants. Data collection was done by trained interviewers, using a structured, pre-tested interviewer-administered questionnaire. Results: The most common symptoms of dengue fever at the acute stage was body ache (81.81%, n=387), followed by headache (71.67%, n=339), loss of appetite (66.80%, n=316), tiredness (53.06 %, n=251) and vomiting (41.86%, n=198). The most common symptom during the post-infection stage was body ache (48.62%, n=230), followed by fatigue (39.74%, n=188), and loss of appetite (28.75%, n=136). Adding sand to the water in places where water accumulates (41.64%, n=197) was the most common method used to prevent transmission of dengue followed by removing/draining stagnant water regularly (36.15%, n=177). Use of mosquito nets (83.08%, n=393) was the most common method in preventing mosquito bites followed by the use of fans among dengue patients (56.02%, n=265). Conclusions: The study shows a prolonged persistence of clinical symptoms during the postinfection period.