Infections caused by arboviruses that have mostly impacted the Brazilian morbidity and mortality are caused by the same vector, Aedes aegypti. Preventive actions related to the vector are the most effective strategies in the prevention and control of these diseases. This study aimed to associate the knowledge on the vector that transmits dengue, Zika and chikungunya with the sociodemographic and behavioral preventive practices towards Aedes aegypti in the municipality of Tangara da Serra, Mato Grosso State, in the Brazilian Legal Amazon. A probabilistic urban population sampling was obtained by clusters: census sectors and households. The sample size calculation considered 10% of loss and a 1.5 design effect. This is a cross-sectional research carried out through a household survey in February and March 2018. There were 583 participants. The study variables were knowledge on the vector, sociodemographic characteristics and preventive practices related to the vector. The statistical analysis was based on a bivariate analysis and Poisson multiple regressions. Inadequate or insufficient knowledge on the vector Aedes aegypti remained associated with education in the categories illiterate (p<0.001) and 8 years of study or less (p<0.001), in addition to not adopting practices of capping and cleaning the water tank (p=0.002) and not using insecticides at home (p=0.007). It is concluded that there is a need for health communication actions that consider characteristics the population, especially the level of education and previous knowledge on the vector, allowing a dialogical approach and enabling the community participation in preventive practices and control of the vector Aedes aegypti .