The exponential increase in plastic production and variable global waste management systems have led to significant amounts of plastic waste entering the oceans annually. The deep ocean is expected to be a major reservoir for plastic pollution, which accumulates over time due to slow degradation rates in cold, oxygen-poor environments. This study conducted a systematic review of published datasets to understand the patterns of macroplastic pollution (>5 mm) on the ocean floor. Using remote-operated vehicles (ROVs) and bottom trawls, the authors built predictive models to estimate the amount and distribution of plastic on the ocean floor. The ROV model, which was better-constrained, estimated that 3 to 11 million metric tons (MMT) of plastic pollution reside on the ocean floor as of 2020, similar to annual inputs from land and significantly more than what is predicted to be floating on the ocean surface. The study also identified key drivers of plastic accumulation, such as shipping intensity, fishing effort, and distance to shore. The authors recommend improved sampling methods, including paired sampling with ROVs and trawls, to better understand the spatial distribution of plastic pollution and improve future predictions. The findings provide a crucial estimate of the ocean floor reservoir of plastic pollution, highlighting the need for enhanced monitoring and remediation efforts.The exponential increase in plastic production and variable global waste management systems have led to significant amounts of plastic waste entering the oceans annually. The deep ocean is expected to be a major reservoir for plastic pollution, which accumulates over time due to slow degradation rates in cold, oxygen-poor environments. This study conducted a systematic review of published datasets to understand the patterns of macroplastic pollution (>5 mm) on the ocean floor. Using remote-operated vehicles (ROVs) and bottom trawls, the authors built predictive models to estimate the amount and distribution of plastic on the ocean floor. The ROV model, which was better-constrained, estimated that 3 to 11 million metric tons (MMT) of plastic pollution reside on the ocean floor as of 2020, similar to annual inputs from land and significantly more than what is predicted to be floating on the ocean surface. The study also identified key drivers of plastic accumulation, such as shipping intensity, fishing effort, and distance to shore. The authors recommend improved sampling methods, including paired sampling with ROVs and trawls, to better understand the spatial distribution of plastic pollution and improve future predictions. The findings provide a crucial estimate of the ocean floor reservoir of plastic pollution, highlighting the need for enhanced monitoring and remediation efforts.