The objective of this study was to assess the effect of wastewater produced from coffee processing plant on nearby water bodies and human health. A study was conducted around the coffee processing plant in Zimma zone (Ethiopia) to assess the physico-chemical characteristics of effluent generated from this plant. Analysis of the water samples taken from the surrounding water bodies had also been done. It was found, from the present investigation, that the wastewater from coffee processing plant was heavily polluted with organic matter as it showed high concentration of COD (upstream 25,600 mg/l and downstream 15,780 mg/1), BOD (upstream 14,200 mg/l and downstream 10,800 mg/l), phosphate (upstream 7.3 mg/l and downstream 4.6 mg/l), nitrate (upstream 23 mg/l and downstream 10.5 mg/1) and suspended solids (upstream 5870 mg/l and downstream 2080 mg/l) and these concentrations were much higher than the permissible limits prescribed by WHO. It was also found, from this study, that the people residing in the vicinity of this plant were consuming this polluted water and as a result suffered from many diseases like skin irritation, stomach problem, nausea and breathing problem. (c) 2007 Elsevier B.V. All rights reserved.