Peritoneal loose bodies (PLBs) are defined as fibrotic or calcified-free bodies within the peritoneal cavity; they commonly autoamputate from appendices epiploicae that have undergone torsion. Pedunculated, subserosal uterine leiomyomas (PSULs) are subserosal uterine leiomyomas connected to the uterus via a pedicle. In the present report, we describe the case of a PLB that originated from the autoamputation of a PSUL, confirmed based on histological evidence consistent with a uterine leiomyoma and the laparoscopic findings of a broken pedicle. This case clearly demonstrates the potential for a uterine leiomyoma to be the source of a PLB. Our findings contribute to the understanding of the etiological relationship between PLBs and uterine leiomyomas.