The ultrastructural architecture of colostral cells of mothers of pre-
and full-term infants is described. The polymorphonuclears were engag
ed in vivid phagocytosis of fat droplets. Similar findings were observ
ed on tt-ie macrophages. The lymphocytes appeared normal in size and u
ltrastructure. A small number of eosinophils and basophils were also d
etected. The number of colostral Cells was higher in the colostrum of
mothers of preterm newborns. The number of the cells in the colostrum
in mothers of both groups decreased with advancement of lactation.