||Shape grammars have been used in architecture for analysis and synthesis - in the first case, mainly for the characterization of styles and in the later for the generation of novel compositions. The present research proposes the use of shape grammars for establishing guidelines for the requalification of historical areas that have lost their original characteristics due to improper renovations. The use of shape grammars proposed here starts with the definition of a set of rules for characterizing the original style of an area. Based on these rules, the main characteristics of the area are confirmed, such as siting, proportions between walls and openings in the façades, overall dimensions constraints, and so on. Next, the rules of the grammar are transformed, to allow the use of contemporary building materials, as well as the incorporation of contemporary living styles in the new design. Rules must take into account two cases: original buildings that have been inadequately transformed, and buildings that have been completely torn down and will replace been completely replaced by new constructions. Both cases need to be harmonious with the remaining original buildings, however without simply copying the existing style. In both cases, rules have been used to establish the guidelines for the renovations, which resulted in modern urban environments that resemble the original historical sites in terms of spatial relations and proportions. They also create an appropriate environment for the observations of the preserved original buildings, which would otherwise look like aliens in a completely transformed neighborhood. The latter case is very common in most Brazilian cities, especially in the case of São Paulo, where houses from the late 1800´s and early 1900´s are flanked by high rise apartment buildings. In order to develop and test the proposed method, a study will be carried out in a small Brazilian town called Monte Alegre do Sul. The town was chosen because its original urban morphology, developed in the XIXth century, is still relatively well preserved, although part of the original façades have been transformed. The objective of the research is to develop a shape grammar to set guidelines for the re-adaptation of the already renovated façades and reconstruction of other ones in Monte Alegre do Sul.