Quantitative data on patterns of distribution and diversity of grasslands is necessary for conservation planning and sustainable utilization. This is the first study to document and analyse the phytosociological data of grasslands of entire Rajasthan state, India. The data was collected through stratified random sampling method by laying 515 sample plots. The study found 375 species belonging to 188 genera and 46 families. Species diversity (Shannon-Weiner diversity) in seven grassland community types ranged between 2.59 and 3.18. The highest Shannon-Weiner diversity index (H'= 3.18) was found in Aristida-Dichanthium grassland followed by Sehima-Apluda grassland (H' = 3.17). The Simpson diversity index and Similarity index are quite different from each other reveals the uniqueness of these grasslands types. Based on our analysis we are concluding that, saline grasslands and swampy grasslands are narrow-niched and ecologically unique. Analysis showed grasslands of Rajasthan as highly species diverse communities and requires prioritization in the long term conservation planning.