Mazzoni L. Supplementary health judicialization and regulation: effects of ANS rules on judicial decisions [dissertation]. São Paulo: "Faculdade de Medicina, Universidade de São Paulo"; 2020. The numbers on the judicialization of health are growing, as are the criticisms of the National Regulatory Agency for Private Health Insurance and Plans (ANS), responsible for regulating the sector. The Health Plans Law came to discipline an consolidated sector, ten years after the promulgation of the 1988 Constitution. The creation of ANS is part of a moment of activities' privatization, which are now also exercised by the private entity. Competent to issue rules, ANS creates rules for health plan operators, in a scenario where rules of consumer law prevailed. These new rules issued specifically for the segment, but whose validity is often questioned, either by consumers or by the Judiciary itself. The present work seeks to analyze the relationship between judicialization of supplementary health and ANS regulation, through the study of individual lawsuits filed by the São Paulo State Court of Justice, as well as prominent collective actions in the supplementary health sector. The study seeks to verify whether the publication of ANS regulations changes the content of judicial decisions in any sense, as well as analyzes whether the issues addressed by the Judiciary are considered by ANS in the preparation of its regulations that create the sector's rules.