Nature protection has been strongly considered necessary so that natural resources and humanity survival can be maintained. The Brazilian legislation has established the maintenance of protected areas as permanent preservation areas (PPA) and legal reserve areas (LR) on rural farms. However, in recent years these areas have been questioned regarding their possible impact on food production and the socioeconomic vulnerability of farms, especially the ones of small areas and low socioeconomic power, as familiar smallholders. The relation between protected areas and socioeconomic characteristics of the families must be comprehended for the equilibration of their socio, economic and environmental necessities. This doctoral thesis reports on an analysis of the economic impacts of protected areas on familiar smallholders of São Paulo State. The focus is on the comprehension of the elements that hamper the agricultural production on these farms, as well as the observations of regional variations and the relations between characteristics, such as familiar incomes, protected areas and others related to the production (land uses, use of animal and mechanical, fertilizers and liming), access of technical assistance, obtaining of loans and investment, cooperative association and some characteristics of the producer (age, education and experience). Quantitative methods of exploratory univariate, bivariate and multivariate (factor analysis) analyses were applied. Secondary data from the Agricultural Census of 2006 (conducted by IBGE) were used with special tabulation, which enabled the separation of the familiar smallholders into two groups by municipalities: one that had protected areas (PPA and/or LR) in 2006 and another that had no such areas. In agreement with a literature review, the analysis revealed that familiar smallholders have diverse production difficulties, which range from basic factors related to the improvement in the education of the familiar producers to structural factors, as difficulties in marketing, transportation, specialized technical assistance among others. The protected areas were not identified as a barrier for the production of the families, and both groups revealed similar incomes in the year analyzed, as the average annual income per family ranged between four thousand reais and eighteen thousand reais. It can be concluded that protected areas in familiar smallholders should not be considered the main factor that determines a lower familiar income, as it has been argumented. For a socioeconomic and environmental equilibrium in familiar smallholders, the complex agroecologic and agroforestry systems must be managed in the legal reserve and the production barriers for such farms must be eliminated.