Cassia sophera from the family caesalpiniaceae is being used in local traditional medicine for asthma and bronchitis. Powdered leaves of C. sophera was extracted with ethanol and subjected for sequential fractionation with chloroform, ethyl acetate and ethanol respectively. Phytochemical analysis demonstrated the presence of flavonoids and antraquinone glycosides in all of the fractions. In the present study, antiasthmatic activity of parent ethanol extract and chloroform, ethyl acetate and ethanol fractions of C. sophera were evaluated. For the evaluation, carrageenan induced paw edema, histamine induced bronchoconstriction, clonidine and haloperidol induced catalepsy, milk induced leukocytosis, and eosinophilia and passive paw anaphylaxis has performed. The paw edema significantly (p<0.05) inhibited by the parent extract, ethyl acetate, chloroform and ethanol fraction at 4th hr with the percent inhibition 54.2%, 50.4%, 44.3%, 60.7% respectively. In the present study C. sophera significantly (P<0.05) protected the bronchoconstriction in guinea pigs against histamine-induced bronchospasm. The parent extract, ethyl acetate, chloroform and ethanol fractions showed 62.7%, 60%, 55% and 64% protection at 4th hour respectively. The clonidine induced catalepsy was found to be inhibited significantly (P<0.05) by parent extract, ethyl acetate, chloroform and ethanol fraction at 120 min (144.00±4.830, 150.50±9.773 175.33, ±13.990, 142.50 ±4.233 sec). The parent extract, ethyl acetate, chloroform and ethanol fractions failed to revert the haloperidol induced catalepsy. In milk induced leukocytosis, milk treated group showed 4575.0 ±117.44 per cu mm leukocyte. The parent extract, ethyl acetate, chloroform and ethanol fractions reduced leukocyte count (1550.0±78.528, 2083.3±35.746, 2750.0±73.030, 1266.7±72.648 per cu mm resp.) and eosinophil count (38.333±2.216, 82.333±2.1246, 2.500±1.057, 40.500±2.078 per cu mm resp.) where milk treated group showed 137.50 ±3.471 per cu mm of eosinophils. The animals pretreated with parent extract, ethyl acetate, chloroform and ethanol fraction showed significant (p<0.005) inhibition in reducing paw edema in passive paw anaphylaxis with the percent inhibition 49.7%, 25.7%, 38.0%, 46.5% resp. In the present investigation, it can be concluded from the result obtained that C. sophera possesses significant antiasthmatic activity.