Cell-derived ECM have emerged as promising materials for regenerative medicine due to their ability to recapitulate the native tissue microenvironment. However, little is known about the glycosaminoglycan (GAG) composition of these cell-derived ECM. In a recent study published in Glycoconjugate Journal, researchers from SCERG-iBB, working in collaboration with colleagues from the Rensselaer Polytechnic Institute, characterized three different cell-derived ECM in terms of their GAG content, composition and sulfation patterns using a highly sensitive LC-MS/MS technique. Distinct GAG compositions and disaccharide sulfation patterns were verified for the different cell-derived ECM. Additionally, the effect of decellularization method on the GAG and disaccharide relative composition was also assessed. The method offers a novel approach to determine the GAG composition of cell-derived ECM, which we believe is critical for a better understanding of ECM role in directing cellular responses and has the potential for generating important knowledge for the development of new ECM-like biomaterials for tissue engineering applications.