Rosai Dorfman disease is rare benign disease of lymph nodes but extra nodal sites may also be affected. It was discovered in 1969. Probably this is the first case report of such case in Bangladesh. Recently I found a girl of 14 years old with gradual painless massive cervical lymphadenopathy for six weeks duration with no signs of acute inflammation. Along with lymphadenopathy she had mild low grade fever. The common probable causes of lymphadepathy were excluded by history, physical examination and laboratory examination. Excisional biopsy and later histopathology confirmed the case as Rosai Dorfman disease. This disease usually follows a benign course and does not require any treatment other then periodic follow up. In course of time it gradually subside. In our case the patient comes every month for follow up. She is doing better now, there is mild regression of the size of lymphnodes. She is attending school regularly and appearing in exams as well. Now our patient is receiving vitamins & occasional paracetamol only.