Introduction: Venous thromboembolism is a burden on healthcare systems. The aim of this analysis was to project the long-term costs and outcomes for rivaroxaban compared to standard of care (enoxaparin/warfarin) in Portugal for the treatment and secondary prevention of venous thromboembolism. Material and Methods: A Markov model was developed using event rates extracted from the EINSTEIN trials supplemented with literature-based estimates of longer-term outcomes. Core outcomes included per patient costs and quality-adjusted life years reported separately per treatment arm and incrementally, as well as cost per quality-adjusted life years gained. The deep vein thrombosis and pulmonary embolism indications were analysed separately. The analyses were conducted from the Portuguese societal perspective and over a 5-year time horizon. Costs and outcomes were discounted at a 5% annual rate. Several scenario analyses were undertaken to explore the impact on results of varying key modeling assumptions. Results: Rivaroxaban treatment was associated with cost-savings for the treatment of deep vein thrombosis and was both cost-saving and more effective for the treatment of pulmonary embolism, compared with enoxaparin/warfarin. Discussion: The results of the sensitivity and scenario analyses further supported that rivaroxaban is a cost-effective alternative to standard of care treatment. The use of an expert panel to derive some input values and the lack of Portuguese specific utilities were the main limitations. Conclusion: Rivaroxaban represents an efficient alternative to using enoxaparin/warfarin in Portugal, as it's associated with lower costs (for both indications) and greater quality adjusted life years (for the pulmonary embolism indication). Keywords: Cost-Benefit Analysis; Venous Thrombosis; Pulmonary Embolism; Rivaroxaban; Venous Thromboembolism. O tromboembolismo venoso representa uma carga substancial para os sistemas de saúde. O objectivo foi estimar os resultados clínicos e económicos a longo-prazo associados a rivaroxabano relativamente à prática clínica (enoxaparina/varfarina) no tratamento e prevenção secundária de tromboembolismo venoso em Portugal. Material e Métodos: Foi desenvolvido um modelo de Markov baseado nos ensaios clínicos EINSTEIN e dados da literatura para complicações a longo-prazo. Foram avaliados custos e anos de vida ajustados pela qualidade de vida totais e incrementais e rácio custo-efectividade incremental. As indicações trombose venosa profunda e embolismo pulmonar foram analisados separadamente. Adoptou-se a perspectiva da sociedade portuguesa e um horizonte temporal de cinco anos. Aplicou-se uma taxa de actualização de cinco por cento para custos e consequências. Foram desenvolvidas análises de sensibilidade e diversas análises de cenário para avaliação da variação dos resultados em função de determinados pressupostos. Resultados: Rivaroxabano está associado a menores custos na trombose venosa profunda e constitui uma alternativa associada a menores custos e a maior eficácia ...