Abstract The intestinal epithelium of Prochilodus scrofa, a freshwater teleost fish, was studied by means of light microscopic techniques. The samples were obtained from the initial, middle and terminal portions of each intestinal loop. The pyloric caeca are lined by a simple columnar epithelium with a small striated border and a very thick basal membrane. Goblet cells, lymphocytes and eosinophil granular cells (ECGs) were observed in the epithelium of all the intestinal loops. The lamina propria of the third intestinal loop is characterized by a high glandular density. At the fourth loop and up to the rectal segment, thick flaps of mucous membrane project into the lumen, resembling the valves found in mammalian veins, apparently preventing the reflux of intestinal contents. At the fourth and fifth intestinal loops an intense intraepithelial invasion of phagocytic cells occurs (macrophage, ECG and lymphocyte). Goblet cell concentration is higher at the sixth intestinal loop and rectal segment.