Diversity of acridids in Muthupet mangrove forest in Thiruvarur District of Tamil Nadu was assessed for a period of one year from April 2013 to March 2014. 1310 grasshoppers belonging to 8 family and 8 species were recorded. The sub family Atractomorphinae (Atractomorpha crenulata) recorded a maximum density of (376) grasshoppers with a population density of 28.7 % followed by the sub family, Orthacris robusta (27.2 %), Oxyinae (Oxya hyla hyla) (13.59 %), Acridinae (Acrida exaltata), (12.4 %), Catantopinae (Diabolocatantops pinguips), (9.16%), Eyprepocnemidinae (Eyprepocnemis alacris alacris) (4.43%), Cyrtacanthacridinae (Cyrtacanthacris tatarica tartarica) (3.05%) and Locustinae (Lucusta migratoria migratoria) (1.91%). Grasshopper population density exhibited temporal variations with the maximum during summer months and a minimum in monsoon months.