Insertion of a LNG-Intra-uterine System (LNG-IUS) has many gynecological indications. The approved indications worldwide are contraception, treatment of abnormal uterine bleeding depending on not organic disease, and endometrial protection in case of an estrogenic therapy. Instead adenomyosis, fibroids, and fertility-sparing management of endometrial hyperplasia or early endometrial cancer in patients with desire of pregnancy are off label indications. Hydroureteronephrosis is an uncommon complication during LNG-IUS insertion. There are few cases described in the literature. The first diagnostic approach for this complication is an abdominal-pelvic ultrasound scan to identify the abnormal position of the device. Diagnostic management includes computed tomography (CT) or magnetic resonance imaging (MRI), which are necessary to confirm hydroureteronephrosis and to assess the exact location of the LNG-IUS in the abdomen. A minimally invasive approach is the standard of care with the removal of the device, while the therapeutic management of the hydroureteronephrosis depends on ureteral and kidney involvement. We report the history of a dislocated LNG-IUS in the left paracervical space with subsequent ipsilateral hydroureteronephrosis. In our case we removed the device through hysteroscopy and later inserted a J-J stent. Follow-up at three months revealed the persistence of left hydroureteronephrosis, so we performed ureter reimplantation. We also performed a review of the literature to analyze common diagnostic and therapeutic pathways for this rare complication.