The analysis and design of masts and towers requires special knowledge and experience, especially when it concerns guyed masts. The special problems related to these structures are underlined by the many collapses during the years. The basis of design for such antenna supporting structures are sometimes many and often mutual contradictory, and the overall structural layout may have a dramatically effect on the loading on the structure. The loads are mainly meteorological from wind and ice and combination of these, and the dynamic nature of the wind has to be taken into account as masts and towers are more or less sensitive to dynamic loads. This paper gives a brief introduction to the problems related to the design, as well as several practical examples are mentioned. The aesthetic elements are becoming more and more important for antenna supporting structures and are also mentioned. The IASS Working Group No. 4 Masts and Towers is the only international forum for the exchange of knowledge and experience within the field of masts and towers, and this Working group is briefly mentioned in the paper.