Urbanization and climate change are two of the most important issues of our days. Many attempts have been made to define the most sustainable way to organise cities in order to cope with the increased population, while simultaneously being climate friendly, socially acceptable and economically viable. This master thesis focuses on the comparison of the sustainability performance of two particular theoretically planned urban forms, located in the suburban area of Stockholm – a “compact city”-like neighborhood and a “garden-city”-like neighbourhood. It was decided that the focus would be on the carbon footprint of the representative residences of each urban form, with the help of Life Cycle Assessment (LCA); and that overall sustainability criteria for neighbourhoods would after wards be assessed, having a certification system forsustainable neighbourhoods (CityLab for districts, in particular) as a framework for a – mostly theoreticalassessment. After the exploring of the differences in the sustainability performance(environmental and social) of the two assessed urban forms, a discussion is made concerning the relationship between urban form and sustainability and conditions under which the most sustainable urban form could be achieved. The results of the analysis highlight that the concept “one size fits all” cannot conform to urban planning decisions, since cities should be able to adjust to the needs of each generation.