This study has been conducted to measure the water quality of Begnas Lake, Pokhara, Nepal. After the collection of different samples from the lake, variety of physico-chemical parameters like hydrogen ion concentration (pH), total hardness (TH), total solid (TS), total dissolved solid (TDS), total alkalinity (TA), calcium (Ca2+), magnesium(Mg2+), Potassium (K+), chloride ion (Cl-), phosphate (PO43-), sulphate(SO4-2), Nitrate (NO3-), ammonium (NH4+)and iron (Fe2+/Fe3+) have been studied in laboratory whereas transparency, temperature, dissolved oxygen( DO) have been noted on the spot. In addition to this, microbial contamination in this lake has been studied in microbiology laboratory to study the presence of coliform bacteria by adopting MPN method. This water contains greater concentration of iron and alkaline earth metal ions along with low oxygen content and high ammonium and carbon dioxide concentration indicating severe rock weathering, open dumping of solid waste, industrial and agricultural effluents in lake water. Various natural and anthropogenic factors have been causing rapid eutrophication and water quality degradation in the lake.