Biomolecule-polymer conjugates are widely used in bio-related fields, but their synthesis is often tricky, especially the introduction of a single biomolecule at one chain end. This paper describes a new straightforward approach to prepare such conjugates via RAFT polymerization. By designing appropriate bio-related RAFT agents, polymer chains of controlled chain length (Mn = 10 000-40 000 and PDI < 1.1) carrying a single biomolecule as an alpha-end group (a sugar or a biotin) linked by a stable amide bond are obtained. Considering the versatility of the RAFT process, this strategy appears to be very attractive for the design of a variety of conjugates.