Since the beginning of its activity IRMM (originally CBNM, Central Bureau for Nuclear Measurements) was engaged in measurements of parameters relevant to nuclear energy. High-purity samples and targets of radioactive materials required for measurements of cross-sections and studies of fission fragments or fuel elements were prepared by the IRMM's target group by means of various techniques reviewed in this presentation. Applying these techniques the target group had been preparing targets of U, Pu, Np, Am, Th for in-house physicists and for external customers.Recently, after a long process of decontamination and refurbishment of the old equipment, custom-made 233 U and 235 U targets were prepared by electro-deposition and by high-vacuum evaporation. Other actinide targets (U, Th) have been prepared using mechanical reshaping techniques.