A brief historical background of the development of the theranostic approach in nuclear medicine is given and seven theranostic pairs of radionuclides, namely 44g Sc/ 47 Sc, 64 Cu/ 67 Cu, 83 Sr/ 90 Sr, 86 Y/ 90 Y, 124 I/ 131 I, 152 Tb/ 161 Tb and 152 Tb/ 149 Tb, are considered. The first six pairs consist of a positron and a β −-emitter whereas the seventh pair consists of a positron and an α-particle emitter. The decay properties of all those radionuclides are briefly mentioned and their production methodologies are discussed. The positron emitters 64 Cu, 86 Y and 124 I are commonly produced in sufficient quantities via the (p,n) reaction on the respective highly enriched target isotope. A clinical scale production of the positron emitter 44g Sc has been achieved via the generator route as well as via the (p,n) reaction, but further development work is necessary. The positron emitters 83 Sr and 152 Tb are under development. Among the therapeutic radionuclides, 89 Sr, 90 Y and 131 I are commercially available and 161 Tb can also be produced in sufficient quantity at a nuclear reactor. Great efforts are presently underway to produce 47 Sc and 67 Cu via neutron, photon and charged particle induced reactions. The radionuclide 149 Tb is unique because it is an α-particle emitter. The present method of production of 152 Tb and 149 Tb involves the use of the spallation process in combination with an on-line mass separator. The role of some emerging irradiation facilities in the production of special radionuclides is discussed.