Present study was aimed to observe the monthly variations in selected physico-chemical parameters of surface water of two perennial ponds of Madhubani district of Bihar state. Selected parameters were determined for one year that is from January to December in 2018. The maximum value of water pH, temperature, turbidity, alkalinity, transparency, total dissolved solids, dissolved oxygen, free carbon dioxide, Biological Oxygen Demand, Chemical Oxygen Demand, Chloride contents Nitrates and Calcium and Total hardness of the pond situated near R.