A field study was conducted in Southern gulf of lake Tana, Northwest Ethiopia to determine therncomposition and the concentrations of contaminants in wastewater from point sources entering tornthe lake and to investigate the severity of the impact on the lake through fie ld survey andrnlaboratory analysis. The major identified point sources of contaminants were pit latrines andrnseptic tankers at household level, hospital, hotels, regional prison, garages, fuel station andrnreligious institutions.rnPhysico-chemical composition of wastewater and lake water were analyzed. Samples ofrnwastewater at point so urces and water quality measurements of grab samples from the lake wererntaken. Samples were analyzed using standard laboratory instruments and procedures. Analysis ofrntotal coliform and fecal coliform, nutrient enrichment and organic concentration profiles werernmade for samples taken from lake where the wastewater enters. Secondary data that fillrninformation gaps were also used.rnThe mean values of major contaminants from wastewater were 1698 mg/l for NO)-, 135 mgll forrnPO.)- and 162 mg/l for NH/. Whereas the mean value of these contaminants from the lake werernfound to be 40 mg/l for NO)-, 0.91 mgll for polo, and 0.57 mg/l for NH/. With regard to majorrncations and anions in the lake, Ca2+ was the dominant cation followed by Mg2+ that accounts forrn62.33 % and 19.84 %, respectively. HCO)- was the major anion dominating, which accounts forrn72.3%. The result also revealed that from the total samples taken for bacteriological analysisrnmajority of the samples showed bacterial growth; from these more than 80% was detected forrnfecal coli forms.rnGenerally, the ultimate effect of pollution in the study area is not noticeable yet, however thernresearch findings confi rmed the existence of contaminants that can induce poll ution to the lake.rnThis has resulted due to anthropogenic activities being undertaken near the lake. Before thernpollution level reaches catastrophic stage, the identified institutions for point source pollutionrnshould manage their waste at their compound and responsible government secters shou ld takernappropriate control measures.