Ethiopia is a resourceful and densely populated country often hit by drought and flood disasters that cause great damage to life and property every year. The frequency and intensity of extreme events have increased significantly in recent decades due to climate change and global warming. This study aimed to analyze the historical changes in rainfall and temperature extremes in the Upper Blue Nile Basin of Ethiopia during the periods from 1980 to 2019. The Mann-Kendall nonparametric trend test and the Theil-Sen’s slope estimator were used to estimate annual and seasonal trends. The rainfall and temperature extremes were analyzed with the RClimDex software by selecting ten rainfall and eleven temperature indices. The results showed a positive trend in annual, Belg (March-May) and Bega (October-February) rainfall in more than 54% of the stations and a decreasing trend in Kiremt (June-September) rainfall in 65.4% of the stations. Several extreme rainfall indices showed insignificant positive trends in the basin. Although there is a positive trend in extreme rainfall, the number of consecutive wet days (CWD) and the simple daily intensity index (SDII) show insignificant negative trends in most stations. In addition, a warming trend of the annual and seasonal maximum and minimum temperature and extreme temperature indices were noted. Overall, the increase in extreme rainfall and a warming trend in the extreme temperature indices indicate signs of climate change in the Upper Blue Nile Basin. These results, therefore, highlight the need to plan and implement effective strategies for adapting and mitigating climate change.