Histochemical study of mucopolysaccharides of both mucous secreting and subjacent granular cells of the epidermis of Glossoscolex uruguayensis L (Righi, 1978), has been done. Histochemical tests revealed two major types of mucous cells: large ortochromatic mucous cells and metachromatic mucous cells. The first ones possess alpha-amylase resistant, PAS-positive material, together with little mucic acid, and the latter present a very low rate of neutral mucopolysaccharides and to a variable degree, both carboxylate and sulphate mucopolysaccharides. A third cell type was also detected, presenting a frothy acid like material. Subjacent epidermal granular cells display alpha-amylase resistant, PAS-positive granules, with no acid mucus.