An integrated model for the dynamic response of a floating production storage and off loading (FPSO) object is developed in this thesis. Objects of this type are often moored in high-depth regions of the sea. The integrated model contains calculations of the coupled movements of mooring lines, marine risers and the offshore object. Due to nonlinear properties of the integrated model, all calculations are done in the time domain. The dynamics of mooring lines and marine risers are described in the second chapter. Movements of these elements are three-dimensional; therefore, it is necessary to examine a large displacement model. Inertial, dumping and restoring forces are considered. Hydrostatic and hydrodynamic forces due to the surrounding fluid are incorporated into the total load. The material of the mooring line or marine riser can be considered as nonlinear in the longitudinal deformation calculation. Small flexural deformation and linear moment-deformation ratio are assumed. A large extension value is considered in the calculation of all previously mentioned forces. The dynamics of an offshore object is presented in the third chapter. Hydrodynamic coefficients are calculated in a specified frequency domain. Mapping from the frequency to the time domain is explained. Small displacements of the offshore object are assumed in the presented case. Inertial forces due to structural mass and added mass, dumping forces due to wave radiation and drag resistance, as well as hydrostatic stiffness are considered. The total load incorporates the first and second order wave forces as well as the wind and the sea current forces. A calculation procedure is developed in the fourth chapter. These calculations include all properties of the mooring line, marine riser and offshore object. Coupling is achieved at the connection points between mooring lines, marine risers and the offshore platform. The balance of forces is conditioned at all connection points. Another condition is the equivalence of displacements of mooring lines or of the marine riser top ends and the related connection points. Interaction forces are considered within the balance of forces on an offshore unit as well as on every mooring line and marine riser. In the fifth chapter, a comparison between the integrated model results and approximated analytical solutions is made. The available related results from literature are also compared.