Introduction: Modern day analyzers are generating a number of parameters which with time have gained a lot of clinical significance. The platelet indices have been investigated as prospective platelet activation markers. The aim of this study is to predict the relationship between platelet parameters and cause of thrombocytopenia and their role in predicting prognosis in dengue. Method: It is an observational study conducted at SAKRA World Hospital. The patient’s data, platelet count, MPV and PDW were recorded using standard proforma.Results: The study was conducted on 263 cases of thrombocytopenia that were broadly categorized into three groups- Group A with accelerated platelet destruction, Group B with impaired production and Group C with abnormal pooling. The platelet indices were compared in the three categories. Relationship between the platelet indices were made with severity of thrombocytopenia. Significant relationship was observed between severity of the thrombocytopenia and severity of the disease.Conclusion: Platelet indices can be used as reliable indicators in differentiating hyperdestructive and hypoproductive thrombocytopenia. They also serve as prognostic markers in indicating the severity of disease in dengue patients. Low MPV (13fl) in dengue patients predicted prognosis to severe thrombocytopenia.