Paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic stem cell abnormality resulting from a somatic mutation in the PIG-A gene located on the short arm of the X chromosome. This mutation leads to an intrinsic erythrocyte membrane defect resulting in marked sensitivity to complement action. It is frequently present with recurrent infections, neutropenia and thrombocytopenia, and appears in association with other hematological diseases, such as aplastic anemia and myelodysplastic syndromes. The triad hemolytic anemia pancytopenia and thrombosis makes PNH a unique clinical syndrome. Currently, it is not just rare acquired. And yes, clonal mutational hematopoietic stem cell defect (HSC). PNH occurs at any age, particularly in the young adult, and affects both sexes equally. It has an extremely variable clinical course. The diagnosis of PNH is of fundamental importance, so that its patients can be submitted to the treatments available, and thus obtain a better quality of life. Aim of this work is a literature review on Paroxysmal Nocturnal Hemoglobinuria (PNH): concept, symptoms, diagnosis and treatment. The methodology used was the review of scientific articles and theses published in an online database: Scielo, Lilacs, Bireme, Brazilian Society of Lymphoma and Leukemia, among others. Conclusion: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease that causes red blood cells to break down earlier than they should. Because of the polymorphic clinical picture, PNH has been misdiagnosed and sometimes confused with other pathologies. several treatments that may relieve the symptoms of PNH the most recent is the monoclonal antibody Eculizumab.