From 2000 onwards dengue fever has been occurring at regular intervals in Bangladesh. Ultrasonography is a useful diagnostic procedure. This study was done, keeping this background in mind. Objective of this study was to identify the role of ultrasonography as a useful tool in early diagnosis of dengue haemorrhagic fever. This was a cross-sectional descriptive type of observational study. Results of ultrasonography, haematogy an immunology were observed in 2004 and 2019 in 32 patients on each occasion. In 2004 out of 32 patients 29 had positive ultrsonographic findings supported by corresponding haematological and immunological findings. In 2019 ultrsonography was done in three out of thirty two patients, all three had had positive ultra sonographic findings which were supported by haematological and immunological findings. Dengue fever has serious complications like plasma leakage which manifest in the form of ascites, pleural effusion, thick gallbladder wall etc. If such complications can be detected at an early stage many lives can be saved.