Guyed masts are used for wireless communication, meteorological measurements, and recently, even for power transmission. The behaviour of the mast is non-linear due to its slenderness and compliant 'guy-support' system. The guys also exhibit non-linear behaviour especially at low values of pretension due to possible multimodal excitations and dynamic response to wind turbulence. This paper presents the results of measured wind characteristics and associated dynamic response of a 50 m tall guyed mast located on the east coast of India in ambient wind conditions. The measured root mean square values of displacements have been compared with a patch load method suggested by Davenport and Spalding [4]. The adequacy of current design practice is reviewed, in the light of the full scale experimental observations.