There is observed increasing pollution of environment by nitrosocompounds. Acute intoxication of animals by nitrosocompounds lead to necrosis and chronic exposure to neoplasm. We have little information on the influence of nitrosocompounds on metabolism of glycoconjugates (glycoproteins, glycolipids and proteoglycans) in animals. The aim of our work is evaluation the influence of exposure of rats for 10 and 90 days to N-nitrosodimethylamine (NDMA), on activity of lysosomal exoglycosidases (enzymes hydrolysing terminal sugars in oligosaccharides) in the alimentary tract. It was found that intoxication of rats with NDMA increased specific activity of N-acetyl-b-hexosaminidase, b-galactosidase and a-mannosidase in majority of tissues of rat alimentary tract. Damage the cells of alimentary tract by NDMA or its metabolites, increase activity of exoglycosidases, because damaged tissue elements must be removed by catabolic enzymes before restoration processes can start.