The cellular, architectural and functional changes of transplanted mesenteric lymph nodes in the rats were studied.After the lymph nodes were transplanted with interrupting both of afferent and efferent lymphatics, the nodes gradually depleted the celluar content. One month after operation the recirculating lymphoeytes in the transplanted node were 3.5% of that in the host nodes, while the number of cells of the transplanted node was only 28%. The number of macrophages also decreased obviously. In paracortex,the cells of high endothelial venule (HEV) became flattened ahn HEV disappeared geadually. In the cortex, the germinal centers and follicles also diminished considerbly in number and disappered completely in 3 month. It was difficult to distinguish the normal compartments in the operated nodes 3 months after transplantation. NO regenerated afferent lymphatics were identified in the transplanted nodes. Lacking of antigen and stimulated lymphocytes brought histological and functional involution of the transplanted lymph nodes.