The intestinal absorption of chondroitin sulfate (CS) and its hydrolysate, particularly the disaccharides (Di-CS), was investigated by using human intestinal epithelial Caco-2 cell monolayers. Although the transepithelial transport of CS was not detectable, dose- and time-dependent transport of Di-CS was observed. The transport of Di-CS was proved to be energy-independent and its permeability increased inversely with the transepithelial electrical resistance (TER) value of the Caco-2 cell monolayers. The transport rate for Di-CS was also increased by treating the cell monolayers with such tight junction-opening agents as interferon-gamma. These results suggest that Di-CS permeated across the Caco-2 cell monolayers mainly via the paracellular pathway. The permeability of Caco-2 cell monolayers to authentic chondroitin 4-sulfate disaccharides (Di-4S), chondroitin 6-sulfate disaccharides (Di-6S) and chondroitin 0-sulfate disaccharides (Di-0S) was almost same, suggesting that sulfation did not affect the transport rate of Di-CS.