A study was conducted to characterize Bahir Dar tannery effluent and determine its impact on the head of Blue Nile River using selected physicochemical parameters. Samples were taken from the direct effluent stream and four sampling sites (one upstream and three downstream) were selected along the river to determine its impact on the river. Samples were collected from October to March, 2010/11. Temperature, pH, conductivity and total dissolved solids (TDS) were measured in situ using a combined meter.