Radiopharmaceuticals have a long tradition of clinical and research applications. Current legislation of developed Countries includes these compounds in the regulatory environment of medicinal products. Products used under a marketing authorisation license and investigational radiopharmaceuticals are then part of the clinical practice and scientific programs. Positron Emission Tomography has induced a strong increase in the number of potentially available radiopharmaceuticals and, beside being a breakthrough in diagnostic nuclear medicine, has demostrated its value as research tool. Drug Development Research is searching new tools for reducing attrition and increasing efficiency in the identification and development of new medicines. Molecular Imaging, PET in particular seems to have important answers to this demand. The regulatory environment in Europe is hence revised in the perspective of utilisation of nuclear molecular imaging as a supporting tool for DDR. Relevant documents from European regulatory Agency (EMEA) as well as their essential impact on radiopharmaceuticals have been summarised and discussed.