The engineering problem of two floating bodies in close proximity occurs in the case of a floating natural liquefied gas terminal when the gas is transferred from a gas carrier to a gas storage and regasification unit. An integral part of the design of such a terminal is the calculation of loads due to the incident waves. The calculation includes the assessment of first order wave forces as well as hydrodynamic reactions i.e. the added mass and the radiational damping. The calculation is based on potential flow theory with the use of three-dimensional boundary element method. Compared to the case of one floating body, the case of two bodies is more complex because it contains 12 degrees of freedom i.e. 6 degrees of freedom for each body. Therefore, the hydrodynamic coefficients and the incident waves forces must contain the interaction of the floating bodies which are in close proximity. The paper presents the results of calculations, done for two barges, which contain transfer response functions and significant force values for given sea conditions.