Background: Dengue infections can occur as epidemics in India causing high morbidity and mortality. The awareness of risk factors can help in early recognising and treatment of severe forms and reduction in mortality. Age is one such intrinsic risk factor which can affect the outcome to a significant extent. Objective: To analyse the haematological variables affected by different age groups and its impact by comparison with other similar or clinical studies on complications of dengue. Materials and Methods: A total of 132 serologically proven Dengue positive cases were analysed along with relevant haematology data after tabulation against patients unique hospital identification number, age and sex. The data was collected over a one month period in November 2016 in Haematology Department of KIMS Hospital and Research Centre, Bengaluru. Results: Our study showed an age range between 5 months to 65 years with most patients in the 12-25 years group and an average of 32 years. We had 30% paediatric cases (≤12 years) and 70% non-paediatric cases (>12 years). The male to female ratio was 1.2:1 with a slight male predominance. The analysis of haematocrit patterns in association with age showed 70% paediatric cases with rise in haematocrit above reference range in comparison to 43% in adults. The highest haematocrit was 59.6 in adults as against to 47% in paediatric cases. Total white cell count patterns were uniform in both groups. The lowest count was noted in adults (1100 cells/cumm) as against paediatric (1900 cells/cumm) cases. The differential count showed marginal increase in lymphocytosis in non-paediatric (70%) as against paediatric (63%) cases, whereas neutrophilia (23% vs 50%) in paediatric and non- paediatric cases was more significant. Neutropenia was seen in a higher proportion of non- paediatric (38%) vs paediatric cases (18%). Platelet counts less than 1.0 lakhs/cumm was noted in 98% in non-paediatric as against 90% of paediatric cases. There was a significantly higher proportion of NS1 Antigen positivity noted in non-paediatric (34%) as against paediatric (15%). Paediatric cases had a higher association (85%) with antibody pattern as against non-paediatric (65%) cases. Conclusion: Age has a significant impact as a prognosticator in dengue and can play an important and decisive role in early diagnosis and management of severe cases.