The aim of this study was to set up a depolymerization process which resulted in the formation of a low molecular weight dermatan sulphate (LMWDS), retaining the chemical properties possessed by native dermatan sulphate (DS), fundamental for the expression of its specific biological activity. The depolymerization of DS by a beta elimination process led to the production of oligosaccharide chains having a 4,5 unsaturated uronic acid at the nonreducing end. The chemical evaluation has shown that the most important parameters (degree of sulphation, sulphate to carboxyl ratio, and specific rotation) have not undergone any particular modification compared to native DS. The biochemical results demonstrate that the LMWDS obtained retains most, if not all, of the specific biological activity. The reduction in molecular weight significantly enhanced the bioavailability of the product after subcutaneous administration.