The Main Ethiopian Rift Valley lakes suffer from water levelrnfluctuations due to several natural and anthropogenic factors. Lakesrnlocated at terminal positions (no surface water outflow) are highlyrnaffected by the fluctuations. These fluctuations are disturbing thernstability of the ecosystems, putting very serious impacts on the livesrnof many animals and plants around the lakes. Hence, studying thernhydrodynamics of the lakes was found to be very essential. Thernmain purpose of this study is to find the most significant factors thatrncontribute to the water level fluctuations and also to quantify thernfluctuations so as to identify the lakes that need special attention.rnThe research methodology includes correlation and least squaresrnregression of lake levels on rainfall, discharge and evaporation,rnmulti-temporal satellite image analysis and land use changernassessment. The results of the study revealed that much of thernfluctuations in the lake water levels are caused by human activitiesrnespecially for the lakes in the Central Ethiopian Rift. Lakes Abiyata,rnChamo, Ziway and Langano are declining while Abaya and Hawassarnare rising. Among the studied lakes, Abiyata is drastically reduced inrnsize (about 28% of its area in 1986) due to both human activitiesrn(most dominant ones) and natural factors. The other seriouslyrnaffected lake is Chamo with about 11% reduction in its arearnbetween 1986 and 2010. Lake Abaya was found to be relativelyrnstable during this period (showed only a 0.8% increase in its area).rnKeywords: Correlation, fluctuation, hydrodynamics, lake level,rnLandsat satellite images, land use change, least squaresrnregression.