35-41Samples of rainwater were collected at a rural environment in eastern Uttar Pradesh at Ballia using 24-h sampling period from July to September 2001. Bulk collector was used for collection of rainwater. All samples were analyzed for major ions (Cl-, SO42-, NO3-, NH4+, Na+, K+, Ca2+ and Mg2+) and pH. Concentration of bicarbonate ion was also computed by a theoretical method. Ammonium, calcium and sulphate were found to have the highest concentrations in rainwater. Volume weighted mean of H+ showed that on an average pH was in alkaline range (6.32 ± 0.16) and varied from 6.1 to 6.8. Equivalent concentration of components followed the order: NH4+ > Ca2+ > SO42- > HCO3- > NO3- > Cl- > Na+ > Mg2+ > K+ > H+. Chemical composition of rainwater at Ballia was similar to that observed at other sites in India except with regard to the concentration of ammonium. High concentration of ammonium in rainwater in this region is due to agricultural activity, human and animal excretion. Fractional acidity was calculated and found to be very less (0.01), indicating that most of the acidity (99%) was neutralized by alkaline component