The present paper discusses the wind force coefficients for designing the main wind force resisting system of a hyperbolic paraboloid (H.P.) free roof, based on a wind tunnel experiment. In the experiment, the lift coefficient (C L) and the aerodynamic moment coefficients (C Mx and C My) about two horizontal axes ( x and y) were measured by using a force balance that had been designed, built and gauged for the purpose of the present study. Correlations between wind force and moment coefficients are investigated, and appropriate wind force coefficients for the design of main wind force resisting systems are proposed for two wind directions perpendicular to each other. The roof is assumed rigid and simply supported by four corner columns, whose axial forces are regarded as the most important load effect for discussing the design wind loads. Two load cases generating the maximum tension and compression of columns are considered. The roof is divided into the windward and leeward halves for each wind direction, and the wind force coefficients on these halves are provided. The proposed values are compared with the specifications of the Australia/New Zealand Standard from the viewpoint of load effect.