Considering the evidences showed in several studies indicating that the genetic polymorphisms can have influence in PCOS and the lack of studies in the Brazilian population, the aim of this study was to investigate the association of the genetic variants of the folate metabolism genes (MTHFR C677T – rs1801133, MTHFR A1298C – rs1801131, MTR A2756G – rs1805087, MTRR A66G – rs1801394 and RFC-1 A80G – rs1051266 polymorphisms with the development of PCOS). The gene discussed is MTR; the disease is polycystic ovary syndrome.