This cross sectional study was carried out in the Department of Radiology and Imaging, Bangabandhu Sheikh Mujib Medical University, Bangladesh in collaboration with the Department of Endocrinology and Department of Histopathology of the same hospital during the period of March 2007 to February 2008 to determine efficacy of ultrasonogram in the evaluation of thyroiditis and to compare its results with color flow Doppler study. For this purpose, a total of 50 patients having clinical suspicion of thyroiditis were enrolled in this study. Ultrasound and color Doppler were done in all these patients. Then all patients underwent for FNAC in the Histopathology department. Correlation between sonographic diagnosis and histopathological diagnosis were observed. Out of these 50 patients 10(20%) were male and 40 (80%) were female with age ranging from 12 to 50 years, highest between 21 to 30 years. The mean age of the patients was 30.42±9.57 years. On unltrasonographic findings of thyroid gland 42.0% patients had regular and 58.0% had irregular margin. Seventy percent had fibrosis, 14.0% had feature of necrosis, 48.0% had lymphadenopathy. Out of all patients 6.0% had normal echogenic feature, 16.0% had increased and 78.0% decreased echogeneic feature. Twelve percent (12.0%) patients had homogeneous and 88.0% had heterogeneous pattern of echogenecity. Thirty eight percent (38%) patients had focal nodules. Sixty percent (60.0%) patients had focal swelling and 40.0% had diffuse swelling. On color flow Doppler 28.0% had normal, 38.0% had increased and 34.0% decreased vascular flow pattern. USG reports revealed that 48.0% had thyromegaly, 36.0% had thyroid nodule, 10.0% had multinodular goiter and 6.0% had thyroid abscess. FNAC diagnosis revealed that 34.0% patients had Hashimoto's thyroiditis, 24.0% had lymphocytic thyroiditis, 18.0% had granulomatous thyroiditis, 6.0% had abscess, 8.0% had goitre and 10.0% nonspecific. USG and CFD are recommended modalities for the diagnosis of thyroiditis as these cost-effective and non invasive procedures.