The Sexual Desire Inventory 2 is a self-report instrument for assessing sexual desire in men and women. In Brazil, there is no validated sexual desire self-report for the adult population. Objective: The aim of this study was to determine the evidence of validity for the content and construct of the Brazilian online version of the Sexual Desire Inventory 2. Methods: This was a cross-sectional study with Brazilian men and women. The sample size was calculated using the criterion of more than 20 participants per item. The invitation to participate in the study was conducted online by the platform Survey Monkey (R). (R) . The Sexual Desire Inventory 2 was evaluated for content, construct, reliability, and invariance. Results: A total of 818 female and male adults participated in the study. The two-dimensional factorial solution represented 71% of the total variance explained by the model, and the factorial loads of the model were >= 0.40; commonalities presented values >= 0.23. Reliability was measured by the coefficients of Cronbach's alpha with a total score of 0.87, McDonald's of 0.87, Omega, and greatest lower bound with a total score of 0.95. The metric invariance was tested for the sex variables Delta CFI (comparative fit index) and Delta RMSEA (root mean square error of approximation) with a total score of 0.01. Conclusion: The analyses indicate evidence of robust validity in the Brazilian online version of the Sexual Desire Inventory 2.