Within a relatively short time, floating production systems have been accepted by the offshore industry as reliable and economic solutions for oil production, also for larger fields. In deeper waters their role seem to become even more important. This move of the floaters into deeper and deeper water brings also new challenges to hydrodynamic offshore research. The aim of this research is to support the hydrodynamics aspects of the design and safe operation of economical offshore structures. The correct prediction of the behaviour of offshore structures during the design of the structure is of vital importance for the reliability and operability of the structure. Taking into account the large investments and risks related to deepwater field development, hydrodynamic research has a small, but important, role. It is generally recognised that model testing of the floaters is an important part of this type of research. But also for model testing the move into deep-water results in a larger number of challenges. These challenges are the subject of the present paper, with at the background the development of MARIN’s new deep water Offshore Basin, which will be completed in May 2000. First the relation between model tests numerical simulations and full-scale measurements will be discussed. Then the requirements for model testing for deep water are highlighted, focussing on the development of the current generation’s system of the new deep water Offshore Basin. Finally solutions for ultra deep water, when even the deepest model basins are not deep enough at traditional model scales, will be presented.