This research deals with the establishment of a hierarchical organization about risks perceived as threadiest and the attitudes underlying such organization. It is based on a preliminary study where the main perceived risks by an urban spanish population were obtained, following the psychometric model. To achieve this objective, a list containing the main perceived risks were presented to a sample of urban subjects with different sociodemographic characteristics. The subject had to chose fifteen risks from the list of all of them, considering which were the most probable for himself/herself to be exposed to, and which worried him/her the most. In order to determine the different hierarchical dimensions, a cluster analysis was carried out which permitted to infer several underlying attitudes in people, that facilitate several threats to be perceived as riskier than others. Within these attitudes we may mention urban pollution concern, house risks, attitudes on power sources and environmental concern. Subsequently, it was studied to what extent these attitudes were different according to several sociodemographic characteristics such as sex, age and learning level.