Intrauterine devices (IUD) used for contraception can be the source of local infections or can migrate, which justifies regular checking recommendations and limitations around the implantation period. To our knowledge, bone and joint infections related to an infected IUD have not been described in the scientific literature. This paper reports on a case of the repeated infection of a total hip prosthesis related to an infected IUD that had been forgotten after being implanted 34years previously. The arthroplasty infection revealed itself through dislocation of a dual mobility cup. Commensal bacteria that colonize the female genital tract (Streptococcus agalactiae) were identified at the site of hip arthroplasty. This led to the discovery of the IUD that was infected by the same bacterium. Despite lavage of the non-loosened arthroplasty, removal of the IUD and 2months of antibiotic treatment, the dislocation recurred and the prosthesis was again infected with the same microorganism 4months later. This recurrence of the infection, with persistence of a uterine abscess containing the same bacterium, was treated with repeated lavage of the joint, total hysterectomy and antibiotics treatment. The infection had resolved when followed-up 3years later. The occurrence of a bone and joint infection with this type of bacterium should trigger the evaluation of a possible IUD infection.