Probabilistic wind loads likely to occur on a structure during its design life are predicted. This article describes a suitable multifactor interactive equation (MFIE) model and its use in the Composite Load Spectra (CLS) computer program to simulate the wind pressure cumulative distribution functions on four sides of a building. The simulated probabilistic wind pressure load was applied to a building frame, and cumulative distribution functions of sway displacements and concepts of reliability were demonstrated by computing the probability of overturning using NESSUS (Numerical Evaluation of Stochastic Structure Under Stress), a stochastic finite-element computer code. The geometry of the building and the properties of building members were also considered as random in the NESSUS analysis. The uncertainties of wind pressure, building geometry, and member section property were quantified in terms of their respective sensitivities on the structural response.