Tanker Based Floating Production Storage and Offloading Systems (FPSOS) are an important component in developing marginal and remote offshore oil fields. This paper provides insight and guidance to operators and designers faced with the many complex issues and tradeoffs involved in selecting a cost-effective FPSO for particular field development conditions. A historical review is included that traces the evolution of the concept from the first installation in 1976 to the present. Useful statistical data on past, present and planned FPSOS is provided. Design drivers, such as production data, service life, site conditions and statutory/regulatory requirements References, figures and tables at end of paper. 221 are discussed. Major selection issues, which include vessel size, type (newbuild or conversion) and mooring system type, and the factors that affect their selection are presented. A case study for a hypothetical field development illustrates a systematic approach to the selection and design of a costeffective FPSO.