Colla　corii　asini　(CCA)　made　from　donkey-hide　has　been　widely　used　as　a　health-care　food　and　an　ingredient　of　traditional　Chinese　medicine.　Heparan　sulfate　(HS)/heparin　is　a　structurally　complex　class　of　glycosaminoglycans　(GAGs)　that　have　been　implicated　in　a　wide　range　of　biological　activities.　However,　their　presence　within　CCA,　and　their　possible　structural　characteristics,　were　previously　unknown.　In　this　study,　GAG　fractions　containing　HS/heparin　were　isolated　from　CCA　and　their　disaccharide　compositions　were　analyzed　by　high　sensitivity　liquid　chromatography-ion　trap/time-of-flight　mass　spectrometry　(LC-MS-ITTOF).　This　revealed　that,　in　addition　to　the　eight　commonly　seen　HS　disaccharides,　the　four　rare　N-unsubstituted　disaccharides　were　also　detected　in　significant　quantities.　The　disaccharide　compositions　varied　significantly　between　HS/heparin　fractions　indicating　chains　with　differing　domain　structures.　This　novel　structural　information　may　lead　to　a　better　understanding　of　the　biological　activities　(i.e.　anticoagulation　and　antitumor　action)　of　CCA.　©　2019,　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.