In the mid-1920s Austrian architect Siegfried Sitte – son of the well-known Camillo Sitte – designed a development plan for the Salzburg municipality of Zell am See. As one of the most significant Alpine tourism hubs under the First Republic, Zell am See was able to maintain its upswing throughout the politically and economically difficult interwar period. In a first profound scientific examination we looked at the planning process and were able to ascertain how Siegfried applied essential planning principles of his famous father Camillo and to what extent. This development plan was created with an in-depth understanding of the local environment and conditions in less than a year, and by considering the topography, the historical buildings and the ownership structure. Siegfried Sitte designed an ambitious plan that aimed to guide the future development of the tourist resort in an orderly manner: the growth was to take place according to a clear hierarchy concerning Zell am See’s scenic landscape. The planning’s main goals were to upgrade the historic city-centre, create a distinctive urban silhouette facing Lake Zell and reorganise traffic along the north-south trade-route. As a new urban gateway to the city special attention was paid to the representative design of the square in front of the railway station. The planning process, which continued until the 1930s, coincides with a phase of political instability in the town of Zell am See, which reflected the disputes between the bourgeois-national and social-democratic camps throughout Austria on a regional level, when the Austro-fascist camp finally took over administration. However, today's urban landscape of Zell am See reveals clear differences from Siegfried Sitte's planning. The paper discusses the features that have been adopted in Zell am See's development structure, as part of a second phase of the inquiry into the urban growth of the Salzburg municipality. It focuses on the similarities and discrepancies between Sitte's development plan and the current situation. A prior assessment of Siegfried Sitte's work revealed that while his planning ideas were closely related to those of his father, Camillo, they were hardly ever put into practice. Consequently, the aim of this article is to address the following questions regarding the urban history of Zell am See: What aspects of the development plan were really implemented and why were there variations from the original concept? To what extent did the political situation affect the planning process and the design of the urban landscape? To what extend does Sitte's design still have relevance for the municipality today, and how viable was it for the Salzburg community overall?