Implantable polymeric medical devices suffer from a lack of visibility under current clinical imaging techniques. To circumvent this problem, poly(3-caprolactone-co-a-triiodobenzoate-3-caprolactone)s (PCL-TIB) containing from 3.5% to 24% of triiodobenzoate-3-caprolactone units were synthesized as new X-ray macromolecular contrast agents. Physico-chemical and thermal properties of PCL-TIBs were evaluated by 1H NMR, SEC, DSC and TGA. Their potential as radio-opacifying additive for medical devices was evaluated by preparing polymeric blends of PCL-TIB with various (co)polyesters. At first, in vitro X-ray visibility of PCL/PCL-TIB blends was evaluated. A more in depth characterization was then carried out based on PCL/PLA50-PEG-PLA50 blends. The impact of PCL-TIB content on the mechanical properties of blends was evaluated by tensile tests. Stability of X-ray visibility was evaluated by ex vivo implantation of non-degraded blends and of blends degraded for 6 weeks in vitro. Finally, cytocompatibility was assessed by evaluating the proliferation of L929 fibroblasts on the blends.