Currently world wide there is an increase in diseases especially infectious diseases that requires efficient body defense mechanisms to control them through the process of immunomodulation. Herbal medicines as the major remedy in traditional system of medicine have been used in medical practices since ancient times. Lepidium sativum Linn. (Brassicaceae) is annual herb regionally referred to as halon in India, however, usually referred to as garden cress. Immunomodulatory activity of n-hexane, chloroform, ethylacetate and methanolic extracts of Lepidium sativum Linn. seeds were studied on albino wistar rats using neutrophil adhesion test. Incubation of blood with nylon fibres produced a decrease in the neutrophil counts due to adhesion of neutrophils to the fibres. Among all extracts methanolic extract showed significant increase in the neutrophil adhesion when compared to disease control and standard. Methanolic extract at 250 and 500 mg/kg produced significant increases in adhesion of neutrophils. Among the different doses of methanolic extract, high one (500mg/kg) was more effective in cellular immunity model than low one (250mg/kg). The results of the present study substantiate the belief that Lepidium sativum Linn. is an immune system booster.