Objective: Subdermal contraceptive implants are a well-established method of contraception. Aside from common side effects such as irregular menstrual periods, headaches, and weight gain, rarer complications related to their insertion and removal have been reported. These include traumatic peripheral neuropathy after procedures to remove nonpalpable implants. Only 2 cases of ulnar neuropathy after insertion of a contraceptive implant have been described in the literature, one which resolved spontaneously and another in which postoperative recovery was not described. We report a case of acute ulnar nerve neuropathy in a patient postinsertion of a contraceptive implant who achieved symptom resolution after prompt referral and treatment at a specialist plastic surgery center. Methods: A 22-year-old, right-hand-dominant woman presented 1 day postinsertion of a contraceptive implant (Implanon) in her left arm with paresthesia along the ulnar distribution of her hand and forearm, as well as shooting pain on palpating the course of the ulnar nerve. Ultrasonography found the implant to be lying in the subfascial plane of the inner arm. Results: The implant was found lying in the perineurium of the ulnar nerve, causing ulnar nerve neuropathy. A review 3 months after removal of the implant showed near-complete resolution of her symptoms. Conclusions: Complications related to implantable contraceptives may lead to significant morbidity. Appropriate training for health care professionals administering the devices is essential, as well as early referral to a specialist center to prevent permanent damage.