Endometrial osseous metaplasia is a rare pathological condition characterized by the presence of bone-like tissue in the endometrium and can be a cause for menstrual abnormalities and infertility as bone in the endometrium can act like an intrauterine contraceptive device. It is a rare entity with an estimated incidence of 3/10,000. Exact etiopathogenesis is not known but the most accepted theory is metaplasia of stromal cells into osteoblast cells, which results in the formation of bones. The possibility of malignant mixed Mullerian tumor should also be kept in mind. Here, we report one such case of primary infertility in a 27-year-old woman presenting with history of oligomenorrhea. Endometrial stromal (osseous) metaplasia is a condition that is rarely seen and may have a potential to be overlooked and misdiagnosed. It is important to recognize the non-neoplastic nature of this condition to avoid misinterpretation as malignant mixed Mullerian tumor of the uterus. Its contraceptive nature makes it an extremely rare but treatable cause of infertility. Complete removal of bony spicules by hysteroscopy can help regain fertility.