[en] Nuclear physics data, or more briefly nuclear data, encompass all quantitative results of nuclear physics research and comprise the areas of nuclear reaction, nuclear structure and nuclear decay data. Nuclear data find widespread use in all branches of nuclear science and technology, with neutron data and radioactive decay data playing a prominent role. A few selected examples may illustrate the fundamental importance of nuclear data for the development of nuclear science and technology. Neutron-induced fission, the means of energy production in nuclear fission reactors, is quantified in terms of nuclear data which are dependent on neutron energy. The fusion reaction between deuterons and tritons, basic to present-day fusion reactor design, is expressed in terms of nuclear data. The decaying nuclide states of fission product and actinide isotopes determine the energy and intensity of alpha-, beta- and gamma-radiation, basic quantities for nuclear waste management, for the shielding of nuclear energy facilities, and for the accounting and safeguarding of fissile nuclear materials