The bioapplications of reversible addition-fragmentation chain transfer (RAFT) polymerization in biomaterials, drug delivery, gene therapy, glycopolymers, and bioconjugates, are reviewed. RAFT agents are organic compounds possessing a thiocarbonylthio moiety. The structures of the R and Z groups are of critical importance to a successful RAFT polymerization. The R group of a RAFT agent is important in the pre-equilibrium stage of the polymerization. For certain monomers, such as MMA, the ability of a RAFT agent to effectively mediate the polymerization is highly dependent on the nature of the R group, whereas other polymerization systems are more resilient with respect to the R group. Functionalities in RAFT polymers are not limited to the choice of monomers, they can also be introduced by polymeric chain end groups. As RAFT becomes established as a commonplace synthetic technique, it is likely to become a vector that favors interdisciplinary collaborations between polymer groups and research teams focused on bioapplications and within hospitals and medical research institutes.