This article brings together two distinct aspects of Aldo Rossi's urban theory and reads them against recent urban peripheral development in Madrid. By exploring the scientific method used in Rossi's work The Architecture of the City against the contemporary conditions of this metropolis, the authors examine whether and to what extent either ‘memory’ or ‘permanence’ are reflected in this new city. Additionally, the analogous city of fragments that Rossi explored in the second phase of his career is also brought into play, and considered in relation to Rossi's scientific method. Developing from Rossi's later approach, we carried out a photographic survey of these areas to understand the contemporary urban landscape. We utilise these two theoretical positions in his work as a form of critique on today's periphery, focusing on two of the Urban Action Plans (PAUs) — Las Tablas and San Chinarro — in the city of Madrid, and bridging the ideas of theory and project that were so important for La Tendenza, the group of architects to which Rossi belonged in the 1960s. These specific study areas allow a broader understanding of the patterns of urban development around Madrid, and the consequences of these projects as experienced by citizens of the city. More broadly, this analysis aims to further our understanding of the European urban peripheral condition, and points to the continuing relevance offered by the theoretical approaches of Rossi's work in today's context, a critical discourse that is felt to be necessary by the authors.