The Nuclear Physics Institute (IKP) consists of four divisions ("Experimental Nuclear Physics I", "Experimental Nuclear Physics II", "Theoretical Nuclear Physics" and "Nuclear Physics Large-Scale Equipment"). The IKP's central task is the operation, use and further development of the COSY cooler synchrotron, an accelerator and storage ring for protons and deuterons. Since the commissioning of COSY (1993) and the associated large experimental installations, the IKP has been conducting basic experimental research in the field of hadron physics in the "non-perturbative range of QCD". For this purpose, proton-proton and proton-nucleus reactions (soon also deuteron-induced) are carried out, which provide information about the subnuclear structure of hadrons (baryons, mesons) and their modification in the nuclear medium. In addition, investigations at external accelerators are carried out to a limited extent, which complement the COSY projects and round off hadron physics research. The projects on nuclear structure physics currently still under way will be completed in the immediate future. In connection with the implementation of a pulsed high-performance spallation source (ESS), the development of a target and of accelerator components has been added to the activities of IKP. Theoretical nuclear physics supports experimental work at COSY and relates it to developments in other fields of nuclear and particle physics. The entire experimental and theoretical programme is carried out with strong participation of scientists from German and foreign universities and research institutions. Research at COSY is supported by the Federal Ministry of Education and Research (BMBF) within the framework of funding basic research in the special field of "hadron and nuclear physics".