Background: Filariasis usually presents as a hydrocoele, lymphoedema, chyluria or a groin lymphadenovarix due to lymphatic obstruction. Atypical presentation of lymphatic filariasis is not common even in endemic areas. We report an unusual presentation of acute filariasis in a patient who had features of peritonitis. Case Report: A 35 year old male from an endemic area for filariasis in India presented with acute lower abdominal pain, distension and scrotal swelling associated with intermittent high-grade fever and non-bilious vomiting. The contrast enhanced computed tomography of abdomen raised the suspiction of a disease involving the lymphatic system. Microfilarial larvae were detected in his peripheral blood smear. He improved with diethylcarbamazine and doxycycline. Conclusion: Surgeons should be aware of the rare and medically treatable causes of acute abdomen like filariasis to avoid the unnecessary surgical intervention. Careful screening of the patients through clinical, laboratory and imaging is of extreme importance to clear the diagnostic dilemma in such cases.