The consideration that mucosubstances act as sites of nucleation and salivary calculi growth prompted to this investigation. Nine calculi of the main excretory duct of the submandibular gland were decalcified and routinely embedded in paraffin. From the blocks serial sections were cut and stained with haematoxylin and eosin and the subsequent histochemical methods for mucosubstances. 1) Alcian Blue-PAS. 2) High Iron Diamine-Alcian Blue. 3) Alcian Blue with critical electrolyte concentration. 4) Alcian Blue before and after testicular hyaluronidase digestion. 5) Acrolein-Thionin-Shiff-PAS 6) Toluidine Blue. Neutral and acid glycoproteins originated from the submandibular gland were predominated in the organic matrix. Glycosaminoglycans probably originated from the connective tissue were detected in the outer areas of the organic matrix. In the central and peripheral parts of 3 salivary calculi spheroid bodies, 1-30 in diameter, were present. The spheroid bodies were unstained with all the histochemical methods for mucosubstances. It is possible the glycoproteins of the submandibular gland to act as nucleating sites in the formation of calculi or, to be passive constituents which are bound by the already formed crystals of the calculi.