Abstract: Physico- chemical characterization of ground water of Chirawa, Buhana and Surajgarh tehsil of Jhunjhunu district have been studied. Water samples from the ground water of villages, colonies, school, hospitals and railway station were collected and analyzed for physico- chemical parameters like ammonia, alkalinity, pH, electrical conductivity, turbidity, TDS, Total hardness, and concentration of ions like chloride, fluoride, nitrate, sulphate, sodium ,potassium, phosphorus, some heavy metal like as Mn and Fe. It has been observed that all parameters were found within desirable limit compared to BIS, but fluoride, potassium, and sodium values are higher compared to WHO. The interesting fact that phosphorus, iron and manganese were not found in any ground water samples. Only fluoride, potassium and sodium are making ground water unfit for drinking.