Darunavir is a protease inhibitor used in the treatment of HIV infection. It is a pillar of therapy cocktail for patients with this virus. This work proposed the development and validation of an infrared spectroscopy method for the determination of darunavir in tablets. The method was completely validated according to the International Conference on Harmonization guidelines, showing accuracy, precision, selectivity, robustness and linearity. It was linear over the concentration range of 1.5-3.5 mg with correlation coefficients greater than 0.9991 and limits of detection and quantification of 0.12 and 0.36 mg, respectively. The validated method is very useful to the routine quality control of darunavir, since it does not use polluting reagents, it is simple and has low-cost.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)