The resilience of the Amazon rainforest to climate and land-use change is of critical importance for biodiversity, regional climate, and the global carbon cycle. Some models project future climate-driven Amazon rainforest dieback and transition to savanna1. Deforestation and climate change, via increasing dry-season length2,3 and drought frequency – with three 1-in-100-year droughts since 20054-6 – may already have pushed the Amazon close to a critical threshold of rainforest dieback7,8. However, others argue that CO2 fertilization should make the forest more resilient9,10. Here we quantify Amazon resilience by applying established indicators11 to remotely-sensed vegetation data with focus on vegetation optical depth (1991-2016), which correlates well with broadleaf tree coverage. We find that the Amazon rainforest has been losing resilience since 2003, consistent with the approach to a critical transition. Resilience is being lost faster in regions with less rainfall, and in parts of the rainforest that are closer to human activity. Given observed increases in dry-season length2,3 and drought frequency4-6, and expanding areas of land use change, loss of resilience is likely to continue. We provide direct empirical evidence that the Amazon rainforest is losing stability, risking dieback with profound implications for biodiversity, carbon storage and climate change at a global scale.