Fibrin is a hydrogel carrier widely used in cartilage tissue engineering. It is rapidly degraded by plasmin, which is produced by the cells. epsilon-Aminocaproic acid (EACA) can be used to inhibit this enzyme and thus save the fibrin carrier. In this study we investigated the effect of EACA on the transforming growth factor beta-1-induced chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs). To assess this, we used the standard pellet culture system, and EACA treatment was compared to an untreated chondrogenic control. To investigate differentiation, real-time RT-PCR was used on chondrocytic marker genes: aggrecan, collagen types II and X, and the SRY-related HMG-box gene 9 (SOX9). Also, specific glycosaminoglycan production was measured. Safranin-O/fast green staining was used to localize proteoglycans and collagens within the pellet. All results concur that EACA did not affect the chondrogenic differentiation process at 5 muM concentration, which is adequate to inhibit fibrin degradation. Therefore, it is a useful plasmin inhibitor for cartilage tissue engineering with hMSCs.