A new high-resolution neutron powder diffractometer has been installed at the 10 MW BER II reactor of the Hahn-Meitner-Institut. The instrument is designed for great flexibility in the choice of wavelength and resolution. A typical collection time for one diffraction pattern is 8 h and the best resolution is close to Deltad/d = 2.10(-3). Profile refinements with up to 100 parameters are feasible to determine crystal structures with cell volumes up to 1000 Angstrom (3).