Mucosa associated lymphoid tissue (MALT) lymphoma can rarely develop primarily in extranodal sites other than stomach which is the most common site for it. Other rare primary sites are small intestine, colorectum, esophagus, lung, thyroid, salivary gland, lacrymal gland, breast and skin. MALT lymphoma represents a distinct clinicopathologic features: it is usually localized to their original site for a long time and shows much more favorable prognosis than lymphoma at other site, but some MALT lymphoma can arise simultaneously or successively in different organ or give rise to another MALT lymphoma of other organ and can be multifocally disseminated or recurred. We report a very rare case of high grade B-cell lymphoma of mucosa associated lymphoid tissue (MALT) of the uterine endometrium, which was confirmed by immunohistochemical assay.