A rare case of malignant transformation of uterine leiomyoma is reported. A 54 year old lady, nulliparous and 2 years postmenopausal presented to gynecology clinic with a pelvi - abdominal mass and ultrasound scan suggestive of multiple uterine fibroid. Total abdominal hysterectomy performed. Histopathology report showed leiomyosarcomative changes from benign leiomyoma within the huge mass.