Floating Production Storage and Offloading (FPSO) vessels are commonly used in Oil \& Gas projects for deep offshore production. They are composed of a production plant (Topsides \& Hull Machinery Space) and accommodations (Living Quarters). Concentration and proximity of noisy equipment to the living quarters increases the risk of unacceptable noise levels. Moreover, offshore workers' comfort and safety are an increasing concern for major Oil \& Gas companies. As it is nearly impossible to reduce noise on operating production units, noise control must be part of design philosophy. Therefore, a global methodology usable from the early design stage and able to control noise throughout the FPSO has been developed based on a mixed approach: \begin{itemize} \item Database built from previous projects, \item High performance FEM calculations, \item Air-borne noise computations, \item Development of specific hybrid methods to estimate structure-borne noise. \end{itemize} This methodology corresponds to project requirements as follows: \begin{itemize} \item First stage design \begin{itemize} \item Noisy equipment identification, \item Preliminary noise studies (including expertise and feasibility analysis), \item Project noise specifications. \end{itemize} \item Detailed design: \begin{itemize} \item Noise and vibration specifications for each critical equipment package, \item Numerical acoustic FPSO models for computation of topside noise mapping, \item Air-borne and structure-borne noise calculation in machinery space and living quarters, \item Design modification definition and validation, experimental validation (N \& V measurements) on critical equipment packages. \end{itemize} \item On-site validation: noise \& vibration measurements in the machinery space and living quarters during yard commissioning, noise measurements on topsides during offshore tests. \end{itemize} After an in-depth presentation of the main steps, different project applications and example results will be evoked and illustrated.