Microplastics (MPs) have emerged as a significant environmental threat, particularly in the Amazon biome. Despite the growing global concern, research on MPs in the Amazon is limited. This study reviews existing scientific knowledge and analyzes population and waste-management data to identify potential sources of MPs in the Amazon hydrographic system. Poor sanitation conditions are identified as a primary source of MPs, with secondary MPs, primarily fibers (96%), composed of polyamide (32%), being the most prevalent. MP concentrations in biota, water, and sediment range from 0.34 to 38.3 particles per individual, 5 to 476,000 particles per cubic meter, and 492.5 to 130.848 million particles per cubic meter, respectively, comparable to heavily polluted areas. MPs are widespread in various Amazonian environments and species, indicating potential ecological impacts. However, limited research, methodological constraints, and lack of standardization hinder the collection of reliable data. The study emphasizes the urgent need for expanded scientific data, improved local research infrastructure, and training to advance understanding and implement effective mitigation measures.Microplastics (MPs) have emerged as a significant environmental threat, particularly in the Amazon biome. Despite the growing global concern, research on MPs in the Amazon is limited. This study reviews existing scientific knowledge and analyzes population and waste-management data to identify potential sources of MPs in the Amazon hydrographic system. Poor sanitation conditions are identified as a primary source of MPs, with secondary MPs, primarily fibers (96%), composed of polyamide (32%), being the most prevalent. MP concentrations in biota, water, and sediment range from 0.34 to 38.3 particles per individual, 5 to 476,000 particles per cubic meter, and 492.5 to 130.848 million particles per cubic meter, respectively, comparable to heavily polluted areas. MPs are widespread in various Amazonian environments and species, indicating potential ecological impacts. However, limited research, methodological constraints, and lack of standardization hinder the collection of reliable data. The study emphasizes the urgent need for expanded scientific data, improved local research infrastructure, and training to advance understanding and implement effective mitigation measures.