The paper deals with production and application of open radioactive sources in modern diagnostic and therapeutic nuclear medicine. In principle, besides adequate physical, chemical and biological properties a reliable route for the routine production of both radionuclide and radiopharmaceutical should be on disposal. The favorite route are radionuclidic generators as they enable simple production of shorter-lived radionuclides at relatively low costs. The main radionuclide in diagnosis is technetium-99m. Its advantages are favorable nuclear properties, availability of large activities of high quality 99mTc at reasonable prices by using (n,f)99Mo/99mTc generators and versatile chemistry. It is used in the investigation of practically all organs and tissues in the human body. Among the betaemitters the radionuclides of rhenium have been recently proposed as suitable candidates for therapeutic applications. The most important is 188Re which is obtained from 188W/188Re generator. Some of the important radiopharmaceuticals labeled with rhenium radionuclides used for certain specific indications are also shown. The activities performed in the Laboratory for Radioisotopes (Vinča Institute of Nuclear Sciences) are also enclosed