The present paper investigates the wind-induced fatigue damage to the beam-column welded joints of flat-roofed low-rise steel buildings under practical conditions of high winds. First, a wind tunnel experiment is conducted to obtain the time histories of wind pressure coefficients at many points on the building. Then, a fatigue test and a finite element elasto-plastic analysis on the welded joints provide data on the fatigue fracture and the relation between the amplitude of local strain at crack initiation location and the number of loading cycles to fatigue fracture (i.e., fatigue curve). Finally, the wind-induced fatigue damage to the welded joints is evaluated using the fatigue curve and the time histories of wind pressure coefficients obtained from the wind tunnel experiment. The results indicate that the local elasto-plastic behavior at the crack initiation location plays a significant role in evaluating the degree of cumulative fatigue damage to the welded joints.