Recently there has been intense interest in the development of fluorinated molecules to allow tracking of therapeutic particles and cells in vivo.The motivation for this is the very high selectivity of the 1gF imaging experiment, since unlike in 1H NMR imaging, the body does not contain a confounding fluorine background signal.In principle therefore, if doubly-tuned MRI coils are available, highly-selective 19F images can be superimposed on high-resolution anatomical 1H images, thus allowing tracking of suitably-labelled biomarker molecules.In this presentation I will describe the current status of magnetic resonance imaging agents with a focus on polymeric agents.This will describe the motivation for the development of new partly-fluorinated copolymers which have outstanding potential as 19F MRI imaging agents[1-3].