This study is for the investigation of the design and analysis processes of filament wound composite pipes under combined loading. The problem is studied by using a computational tool based on the Finite Element Method (ABAQUS). Filament wound pipes are modeled as multi layered orthotropic pipes. Several analyses are performed on layered orthotropic pipes by using FEM. Results of the FEM are examined in order to investigate characteristics of filament wound pipes under different combined loading conditions. Winding angle, level of orthotropy and various ratios of the loading conditions were the main concerns of the study. The results of the FEM analysis are discussed for each loading condition. Both pure loading and combined loading analysis results were consistent with the ones mentioned in literature, such as optimum winding angles, optimum loading ratios and optimum level of orthotropy. Modeling parameters, assumptions and source of errors are also discussed. roperty of composite materials used for pipe construction is the second topic investigated. Nonlinear constitutive equations of the composite material in the through thickness direction are established using a micro-mechanics approach. Finite element analysis of composite pipe integrating fiber failure and material nonlinearity is the third topic. Detailed procedures and analysis based on different failure criteria are present. Failure criteria and the progressive damage accumulation of composites the last topic. A scheme for stiffness reductions due to damage corresponding to different failure criterion such as Puck, Tsai-Wu and Christensen are proposed. These are based on Xu , stiffness degradation theories. Finally, the required data is obtained for the design of filament wound composite pipes under combined loading. Key Words filament wound, composites, finite element analysis, orthotropy.