Odontogenic Myxoma is a benign odontogenic tumor of odontogenic ectomesenchyme with or without included odontogenic epithelium. It is a tumor of the jaw which apparently arises from the mesenchymal portion of the tooth germ either the follicle, dental papilla or the periodontal ligament. It is a central lesion of the jaws which expands the bone and causes destruction. Odontogenic myxoma, an uncommon benign neoplasm comprises about 3–6% of all odontogenic tumors. Some investigators made a distinction between odontogenic myxomas derived from odontogenic mesenchyme and osteogenic myxoma derived from primitive bone tissue. However it has been considered all myxomas of the jaws to be of odontogenic origin.In this article we present a rare case of Odontogenic Myxoma which occurred in the posterior maxilla of a 30 year old female.