1. The study models erosion in the Mizewa watershed in the Upper Blue Nile Basin of Ethiopia using the SWAT model. Erosion rates were high, with average annual soil loss of 40.91 tons/ha. 2. Calibration and validation of the SWAT model showed good performance with R2 and NSE values over 0.5 and fair agreement between observed and simulated results. 3. The highest erosion occurred in July and August due to high rainfall. Surface runoff accounted for 24% of rainfall and was the main driver of erosion in the watershed.