Orange peel wastes (OPW) were extracted with water to remove soluble material, and the resulting solid phase (which was obtained at a yield of 48.8 kg/100 kg of OPW, oven-dry basis) was employed as a substrate for the manufacture of pectic oligosaccharides by nonisothermal processing with hot, compressed water (autohydrolysis or hydrothermal treatments). The effects of treatments on the composition of both liquors and spent solids were assessed in terms of the severity factor (Ro). Operating under selected conditions (maximum temperature of 160 degrees C, corresponding to Ro = 288 min), the oligosaccharide yield (including oligogalacturonides, arabinooligosaccharides, and galactooligosaccharides) accounted for 25.1 kg/100 kg of extracted OPW, whereas limited concentrations monosaccharides and nonsaccharide compounds were present in the reaction media.