In West India, the Hibiscus rosa-sinensis L. (Malvaceae) is traditionally used as tea as a natural diuretic. Extract of this plant contains Vitamin C and is used traditionally as a mild medicine. In spite of a long history of traditional medicinal value of H. rosa-sinensis still no data are available for immunomodulatory activity. In present investigation, aqueous extract of H. rosa-sinensis (AEHrs) (500 mg kg(-1) BW) was intraperitoneally (IP) injected to the male Swiss albino mice (Mus musculus) to evaluate the immunomodulatory property of extract. In addition for evaluation of phytochemical constituents of flowers of H. rosa-sinensis HPTLC was performed. The crude extract of H. rosa-sinensis has immunomodulatory activity. After the 15 days treatment, the number of plaque forming cells increased by 0.6%, antibody titre was increased 38.15% and significant increase of 52% was observed in DTH response. At the same concentration of dose the level of serum IL-1alpha enhanced significantly (14.27%) whereas a considerable decrease (32.70%) in the concentration of IL-2 was observed among AEHrs treated mice in comparison to the control mice. HPTLC chromatogram revealed that H. rosa-sinensis posses alkaloid (Rf 0.93) and flavonoids (Rf 0.02, 0.06, 0.14) on the basis of Rf values. Results of investigation supports for the immunomodulatory activity of H. rosa-sinensis aqueous extract.