Understanding of seasonal changes in vegetation is key to assessment of ecosystem structure and function in arid and semi-arid areas. In the present study we look at the seasonal change in plant community composition which we looked at using the Important Value Index in the Taranagar region of Churu district. We chose 11 sampling sites which we studied before and after the monsoon season. Quantitative parameters such as frequency, density and abundance were measured and IVI used for evaluation of species dominance. We found that which species dominated and which species made up the community changed by season. Drought tolerant species like Verbesina encelioides, Aerva persica and Calotropis procera had higher IVI values in the pre-monsoon season which we take as an indication of their adaptation to low moisture conditions. In that which followed the monsoon post monsoon we saw an increase in the dominance of species like Aerva persica, Calotropis procera & Prosopis cineraria which in turn is an indication of better growth conditions due to the rain. Also, we noted great variation in IVI values between species some which had large scale improvement in dominance, some which did not do as well or at all and which in the end did not even show up in the next season which indicates a seasonal shift. The study also underlined the ecological significance of herbaceous plants in semi-arid conditions by highlighting the spatial variance among sites and their abundance. The observed fluctuations in vegetation form and species composition are largely determined by seasonal rainfall and other environmental conditions.