Eristalis tenax, belonging to order Diptera, family Syrphidae seldomly causes intestinal myiasis. Urinary myiasis caused by Eristalis tenax larvae is a rare manifestation found in both humans and other vertebrate animals. We report a 58-y-old woman presented with painful mixing and bilateral costo-lumbar pain. The larva in her urine sample was identified as Eristalis tenax related to its typical morphology.