In this study we used colloidal gold probes to detect the intracellular localization of colostral immunoglobulins in intestinal epithelial cells of newborn piglets.Tissues were obtained from non-suckled newborn and suckled piglets aged between 1 hour to 1 month. Samples were fixed in 2.5 % glutaraldehyde, osmicated and embedded into Spurr’s resin. Thin (80 nm) sections were etched with 5% sodium ethoxide for 5 min, washed and treated with 4 % sodium-m-periodate in distilled water for 30 min. The sections were then first incubated with blocking buffer (2 % BSA, 0.25 % fish skin gelatin, 0.5 % Tween 20 in 10 mM Trizma buffer, pH=7.4 containing 500 mM NaCl) for 30 min followed by the immunoreagents diluted in the same buffer, 1 hr each. For the detection of pig immunoglobulins a rabbit anti-pig IgG antiserum was used followed by goat anti-rabbit IgG-Au10 or protein A-Au15 probes.