Understanding the link between river flow and rainfall is crucial particularly in dryland areas where there is high spatial and temporal rainfall variability. The purpose of this study is to show the link between rainfall variability and river discharge in Dawa river basin in southern Ethiopia. In order to analyze the surface hydrological effect of rainfall variability, historical rainfall and river flow data from 1972 and 2017 were used. The rainfall data were obtained from the Ethiopian Meteorological Agency, whereas the river flow data was obtained from the Ethiopian Water Resource Agency. The link between rainfall variability and river flow was modeled using linear regression model. During the 1972 - 2017 period, in all seasons, the temporal trends of the rainfall flow and the river flow show decreasing trends. In summer, winter, autumn and springs seasons the rainfall show decreasing trends with annual decrease of. 0.04 mm, 0.064 mm, 0.05 mm and 0.15 mm respectively. While the river flow show decreasing trends in summer, winter, autumn and springs seasons with annual decrease of 2.89 m3 s -1 , 0.26m3 s -1 , 1.08 m3 s -1 and 0.41 m3 s -1 respectively. The result shows that rainfall variability resulted in diminish river flow discharge in annual from the year1972 to 2017 in the study area. Thus, it is recommended that strategies should be designed by the agricultural experts for the agricultural sector for the impacts of declining and erratic nature of rainfall and decreasing trends of river flow in to consideration in their routine activities in the study area.