BACKGROUND Foreign bodies (FBs) in the intra- or extra-peritoneal cavity are relatively rare. The aim of treatment is to remove the FB to prevent chronic inflammation and/or infection. Traditionally, surgical management is necessary, as the detection and localization of FBs can be difficult. Mini-percutaneous nephrolithotomy (Mini-PCNL) under the guidance of ultrasonography (US-guided) has recently been used as an alternative to conventional therapeutic options for FB removal. CASE REPORT In this article, we report the cases of 2 patients with an extra-peritoneal wooden toothpick FB treated using the mini-percutaneous nephrolithotomy technique as an effective treatment for removing the FBs. These patients recovered quickly and were discharged uneventfully. CONCLUSIONS Using ultrasound to guide mini-PCNL represents a potential alternative to laparoscopic surgery for the detection and removal of FBs, allowing the patient to recover quickly. This approach is simple, minimally invasive, and feasible under local anesthesia and should be considered as an alternative to surgery.