Background: Since the etiology of ranula is unknown, treatment is still controversial. However, ranula has recently been speculated due to mucous extravasation into the ambient tissues from a traumatized sublingual gland or duct. Plunging ranula is far less frequently encountered than sublingual type. Furthermore, bilateral presentation was very unusual. We encountered a case of bilateral ... [Show full abstract] plunging ranula, which occurred asynchronously, and treated via different surgical approach. Case report: A 5-year-old girl, who had undergone the removal of a median cervical cyst by Sistrunk method at the age of 2, had swelling in the left submandibular region 9 months before. Magnetic resonance imaging (MRI) revealed a plunging ranula. Excision of ranula and removal of the sublingual gland were performed via a cervical approach and the cyst lining had no epithelium. Contralateral ranula was found by follow-up MRI 6 months after the surgery. Following the previous result, incision of ranula and removal of the sublingual gland were undergone via an intraoral approach. Follow-up at 9 months shows no evidence of recurrence. Conclusion: As treatment of plunging ranula, excision of the sublingual gland appears to be essential for cure, regardless of whether via intraoral or cervical approach. Intraoral excision is more advisable because of its less invasiveness.