<p>The paper describes the design process of the Chacao Bridge in Chile, what have been the challenges in the design, and how these challenges are solved. The bridge is a multi-span suspension bridge with main spans of 1155m and 1055m and with a total length of approximately 2750m, making it the longest suspension bridge in South America, connecting the island of Chiloe to mainland Chile. The bridge site is subjected to severe environmental loads, and particular effort has been on ensuring seismic robustness, since the site is located in a high seismic zone. The detail design is performed by consultants Aas-Jakobsen from Norway and Systra from France for Consorcio Puente Chacao. The bridge owner is MOP Chile.</p>