We propose to use instruments SXD and WISH to carry out a detailed feasibility study of neutron protein crystallography at ISIS. Since one of the major impediments to protein crystallography with neutrons is hydrogen incoherent scattering, we will focus on small protein systems that are perdeuterated. The overall aim of the the study will be to identify the optimal beam conditioning (wavelength spread and brilliance) and timeslicing for small proteins and to develop an understanding of the demands necessary for larger protein systems where time-of-flight instruments could provide significant advantages.