Disclosed is a low-molecular-weight (1000-5000 daltons) chondroitin sulphate (CS) produced by chemical sulphation and subsequent depolymerisation of a non-sulphated chondroitin backbone obtained with biotechnology techniques. The CS described is substantially monosulphated, mainly at the 6-position, with very little sulphation at the 4-position, and with a mono/disulphated disaccharide ratio and charge density similar to those of natural CS. Said biotechnological chondroitin 6-sulphate (C6S) is useful in the treatment and prevention of osteoarthritis and in acute and chronic inflammatory processes.