Primary non-Hodgkin' lymphomas of the liver, an organ normally devoid of a native lymphoid tissue, are very rare. We recently experienced a case of a primary low-grade hepatic B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type in a 36-year-old woman. The ultrasonography revealed a 5 cm sized mass in the right lobe of the liver. A right segmentectomy of the liver was done and showed a relatively well-circumscribed brownish yellow lobulated homogenous mass, measuring 5.5x4.5 cm in size. Histologic sections of liver mass revealed large lymphoid follicles with reactive germinal centers, follicular colonization by centrocyte-like cells (CCL cells), and lymphoepithelial lesions. The CCL cells were positive for B-cell (CD20), LCA (CD45RA), Bcl-2 oncoprotein, and lambda light chain.