The study looked at how Non-Performing Loans (NPL) affect Return On Assets (ROA) at Bank Mandiri from 2007 to 2012. ROA measures how well a bank uses its assets to make profits. The researchers found that NPL has a strong negative relationship with ROA, meaning higher NPL leads to lower ROA. NPL significantly influences 82.05% of ROA, with the remaining 17.95% influenced by other factors. The regression equation shows that for every unit increase in NPL, ROA decreases by 0.95 units.