Isotopic composition of monthly precipitation samples from Warangal, a semi arid region across Southern India was studied for a period of 12 months. During the study period, the region received a average rainfall of 900 mm. The stable isotope (δ18O) values varied from -4.9 %o to 2.4 %o for the precipitation samples throughout the year. The d-excess of precipitation in Warangal revealed that the precipitation in the region undergoes significant modification through secondary evaporation during its fall. The Local meteoric water line for Warangal city is developed. The stable isotope composition of precipitation at Warangal showed significant variation from global trend. These differences are attributed to the higher mean sea elevation of the area as well as climatic conditions.