This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.carres.2015.07.002 ; The carbohydrate moieties of arabinogalactan-proteins (AGPs) have ?-(1?3)-galactan backbones to which side chains of (1?6)-linked ?-Gal residues are attached through O-6. Some of these side chains are further substituted with other sugars. We investigated the structure of l-Fuc-containing oligosaccharides released from the carbohydrate moieties of a radish leaf AGP by digestion with ?-l-arabinofuranosidase, followed by exo-?-(1?3)-galactanase. We detected a series of neutral ?-(1?6)-galactooligosaccharides branching variously at O-3 of the Gal residues, together with corresponding acidic derivatives terminating in 4-O-methyl-GlcA (4-Me-GlcA) or GlcA at the non-reducing terminals. In neutral oligosaccharides with degree of polymerization (dp) mainly higher than 10, l-Fuc groups were attached through l-Ara residues as the sequence, ?-l-Fucp-(1?2)-?-l-Araf-(1?. This sequence was verified by isolation of the pentasaccharide ?-l-Fuc-(1?2)-?-l-Araf-(1?3)-?-Gal-(1?6)-?-Gal-(1?6)-Gal upon digestion of the higher oligosaccharides with endo-?-(1?6)-galactanase. By contrast, in lower polymerized (predominantly dp 4) acidic oligosaccharides, l-Fuc groups were attached directly at the non-reducing terminals through ?-(1?2)-linkages, resulting in the release of the tetrasaccharides, ?-l-Fucp-(1?2)-?-GlcA-(1?6)-?-Gal-(1?6)-Gal and ?-l-Fucp-(1?2)-?-4-Me-GlcA-(1?6)-?-Gal-(1?6)-Gal. In long acidic oligosaccharides with dp mainly higher than 13, l-Fuc groups localized on branches were attached to the uronic acids directly and/or l-Ara residues as in the neutral oligosaccharides. ; The authors would like to thank Prof. M. Hisamatsu, Mie University, Tsu, Japan, for a gift of cyclic ?-(1?2)-glucan. This work was supported by the Ministry of Education, Culture, Sports, Science, and Technology of Japan (Grant-in-Aid for Scientific Research no. 23570048 to Y.T. and no. 24114006 to Y.T. and T.K.). Support was also provided by BBSRC Sustainable Bioenergy Centre: Cell wall sugars program (Grant No. BB/G016240/1) to P.D.