Galactan biopolymers have shown important biologic properties, such as antiviral, antitumoral and anticoagulant activity. The synthesis and isolation of oligosaccharide sequences with such activities may result in new drug discoveries. The aim of this work was the production of reducing oligosaccharides, which are substrates adequate for chemical modifications, from galactan biopolymers. For this purpose commercial agarose was submitted to partial hydrolysis (TFA 0.1M, 65^oC, 2 hours). The oligosaccharide mixture was purified through gel filtration chromatography in Bio-Gel P-2, yielding two principal fractions: AA and AB. These fractions were analysed by NMR spectroscopy and the spectra showed that the following reducing oligosaccharides were isolated: agarobiose (b-D-galactopyranose-(1®4)-3,6-anhydro-L-galactose) and agarotetrose for AA and AB, respectively. These molecules showed high degree of purity and were used as standards in the development of a HPLC method that allowed us to follow the hydrolytic process. In six hours, nearly fifty percent of oligosaccharide products corresponded to agarobiose (33%) and agarotetrose (18%). These results demonstrated that the partial hydrolysis method and the purification technique used in this study allowed the isolation of reducing oligosaccharides containing 3,6-anhydro-galactose at the reducing terminal end. The best time found to obtain high amounts of these molecules was six hours of hydrolysis.  In this manner, these oligosaccharides are been used as carbohydrate donors in the semi-synthesis of neo-glycosides.