OBJECTIVE: to study the changes in health-related quality of life from beginning of anticoagulation therapy to six-month follow-up, and to study associations of sociodemographic and clinical characteristics with measures of quality of life and general health status at six-month follow-up, in individuals using oral anticoagulation due to various medical indications for the therapy. METHOD: prospective study performed at a city in the state of Paraná, Brazil, composed of 78 patients. Measures included the Duke Anticoagulation Satisfaction Scale and the Medical Outcomes Survey Short Form SF-36. RESULTS: mean age was 57 years (S.D.= 16) and 54% were women. Compared to the beginning of therapy, there was a statistically significant improvement in health-related quality of life at six-month follow-up. Linear regression analyses explained 32% and 30%, respectively, of the variance of the Duke Anticoagulation Satisfaction Scale and of the general health status. There was improvement in all components of the SF-36, except Mental Health. CONCLUSION: The use of oral anticoagulation therapy was associated with improvement in health-related quality of life in the first six months of therapy. This study is longitudinal and therefore, has fewer limitations than cross-sectional studies published to date in the Nursing literature in Brazil.