This article was mainly aimed to compare the quality of life of a group of patients according to the point of time when their diagnosis was provided: either recent (less than a month), or later (six to twelve months), and was conducted with four patient groups with chronic diseases such as hypertension, diabetes, asthma and migraine. Eighty patients from the Mexican Health Service [Instituto Mexicano del Seguro Social (IMSS)] participated in the study. Life quality was evaluated through the application of an instrument elaborated specifically for the Mexican population which includes 86 items distributed in the following categories: sexual, familiar and interpersonal, personal care and appearance, working areas, emotive-affective, self-concept, academic and socioeconomic level. The most significant variables were: point of time when the diagnosis was provided, academic level and years of service in an employment. Results show certain differences when comparing time of diagnosis, academic level (school years) and occupation (measured in years of service). On the other hand, the symptoms of each ailment have an impact in the self-control and self-concept of the patients, phenomena closely linked to their life quality.