The management of urban environment, together with the preservation of the natural environment and the creation of a sustainable built environment, is a complex challenge for contemporary societies. In the name of progress, cities are contributing for the degradation of all surrounding ecosystems. Therefore there is an arising demand for developing new strategies and a new urban development paradigm settled in the search for the equilibrium between natural and built environments and efficient use of resources. The objective of this paper is to analyse how the urban expansion of the city of Estarreja took place in relation to the land use, based on the land capability classification maps of the area. Based in the results some sustainable development strategies that might be applied to the city are discussed. The obtained results demonstrate that the city has been growing faster than its population, consuming vast portions of land, since its growth has been occurring in a linear form. Despite this fact, results show that most of this expansion took place towards a territory of lower agricultural potential, when comparing to the location of its original settlement. Keywords: sustainable urban development, urban sustainability assessment, rational land use.