An effort was made here to examine the behaviour of Indian Summer Monsoon Rainfall (ISMR) at regional level in the state of Haryana. The monthly monsoon rainfall data of recent 30 years (1988-2017) of distinct stations of the state was used for the exploration. The mean rainfall during ISMR in the state ranged from 248.04 mm at Sirsa and 956.94 mm at Ambala. Monthly mean rainfall ranged between 43.55 and 134.09 mm (June), 81.23 and 340.21 mm (July), 68.76 and 331.23 mm (August) and 54.51 and 175.35 mm (September) at different locations. The significant portion of ISMR occurred during the month of July and August in the study area. Monthly mean rainfall during June, July, August and September at different locations ranged from 43.55 to 134.09 mm, 81.23 and 340.21 mm, 68.76 to 331.23 mm and 54.51 to 175.35 mm, respectively. An overall decreasing trend in ISMR was observed at all the locations during the course of study period.