The Pediatric Quality of Life Inventory (PedsQL) 4.0 is a questionnaire that evaluates the health related quality of life of children and adolescents, considering different aspects of their development, including the physical, emotional, social and educational. We verified the impact of demographic, social, and economic factors, as well as the family situation, on the health related quality of life of a group of school children of the city of São Paulo, Brazil. The PedsQL 4.0 was applied to 240 children and adolescents aged 2 to 18 and their respective parents. More than two thirds of the families were from lower social strata (C, D, and E). A statistically significant difference was observed in scores when evaluating the health related quality of life across socioeconomic strata and we observed statistically significant differences in the emotional, social, psychosocial and total scores. The PedsQL 4.0 scores obtained through interviews were satisfactory when compared with other urban populations of children and adolescents, probably due to the homogeneity of the population studied.