The vanadium is a metallic oligoelement present in the majority of tissues. Its abnormal biological disposal environment can be related with its possible teratogenicity and alteration in the contents of glycosaminoglycans acids (GAGs), which participate in the morphological processes and the maturation of Central Nervous System (CNS). The proposal of the project is to analyze the teratogenic effect of ammonium metavanadate (AMV) and its action on the GAGs in the CNS of the litter of albino rats. The ammonium metavanadate was diluted in distilled water in concentration of 100 and 200 ppm, drunk by the rats since their birth and/or weaning to adult age, except during the matching and gestation. The animals control drunk water without this metal. The litter were analyzed to detect possible congenital malformations, then CNS were removed of descendents and were processed by light microscope, cuts of 6 u were stained with H/E; Alcian Blue pH 3.5 and 5.6, this last one concentrations of C12Mg from 0.05 M to until 1.0 M. Previously parallels sections were treated with testicular hyaluronidase. The macroscopic analysis of the new born rats that came from rats that received AMV in concentrations 100 and 200 ppm, resulted in congenital anomalies like unilateral hypoplasia of olfactory bulbs and cerebral hemisphere. The microscopic analysis revealed changes in the layers patron of olfactory bulbs and an increased of alcianophilia in the pH 5.6 to 0.2 M MgC12, in the extracellular matrix of CNS of rats descendents treated with AMV to the dose 200 ppm, sensibles to the testicular hyaluronidase, corresponding to hyaluronic acid (HA) and chondroitin 4 and/or 6 sulphate (C4S or C6S) of low grade of sulphation. These results suggest that the AMV given to albino rats has a teratogenic result when it is used before the gestation and for long periods of animals life that alter the of GAGs of CNS contents during the development.