The former FIP Commission Prefabrication drafted the FIP Recommendations on the design of Precast prestressed hollow core floors, published by FIP in 1988 (Telford, London, ISBN 0-7277-1375-2). That document was highly appreciated by designers and public authorities because of the lack of guidance available elsewhere, especially with respect to some specific features of the product, for example the absence of transverse reinforcement. It has also served as a reference guide for national standards and especially for the CEN product standard on prestressed hollow core slabs. During the production of that report it was felt that some design rules were incomplete or missing. In addition, research carried out since has resulted in complementary knowledge on the behaviour of hollow core floors, for example in combination with slender floor beams. The present guide to good practice is intended to complement the existing recommendations. The research for the different items was carried out at Chalmers University of Technology (Sweden), Politecnico di Torino (Italy), VTT (Finland), University of Nottingham (United Kingdom), Building Research Institute (Poland), and the University of Rome (Italy).