Urbanization may have ecological and economic effects on small-scale fisheries in tropical rivers. However, such effects remain poorly known. Our goal is to evaluate the potential effects of urban development of major cities on small-scale freshwater fisheries in the Brazilian Amazon, through literature review and by using some results of our research in Amazonian rivers. We focused on some study cases around large cities in different Amazonian regions, including Santarém (Eastern Amazon), and Manaus (Central Amazon). We discuss the positive and negative effects of the proximity to urban centers. Negative effects may include overfishing near large urban centers and its ecological consequences, such as a decrease on fish size of both individual species and the size structure of the fish community, changes on fish diversity, and declines on fish catches of small-scale fisheries. Other negative effects include anthropic impacts of deforestation and pollution, such as eutrophication, solid waste (micro-plastics) and heavy metals (mercury). Positive effects may include improved market opportunities for fishers, in the form of increased demand, besides higher proximity to consumers, which may shorten the market chain and make it more profitable. Another positive effect would be the engagement of fishers in tourism and other related activities. Finally, we suggested hypotheses to be tested and new avenues for future research.