Abstract Suspension bridges are long slender flexible structures which have the potential to be susceptible to a variety of types of wind induced vibrations, the most serious of which is the aerodynamic instability known as flutter. In this phenomenon at certain windspeeds aerodynamic forces acting on the deck are of such a nature so as to feed energy into an oscillating structure, so increasing the vibration amplitudes, sometimes to extreme levels where the basic safety of the bridge is threatened. The windspeed at which flutter occurs for completed bridges depends largely on its natural frequencies in vertical flexure and torsion and on the shape of the deck section which determines the aerodynamic forces acting. One computational method (based on numerically integrating the equations of motion) for predicting flutter speeds which was developed for use in the design of a major suspension bridge crossing is described.