To explore antioxidant, and immunomodulator activities of Citrullus lanatus seed extract by utilizing in-vitro models. Hydroalcoholic extract of Citrullus lanatus seeds was prepared and arranged in the different concentrations to study the antioxidant activity by different methods and immunomodulatory activity also.. The present investigation will be supportive to the scientific documentation related in-vitro studies. The DPPH Free radical scavenging assay results revealed that the hydroalchoholic Citrulus lanatus seed extracts were found to have good antioxidant activity. The IC50 value of hydrogen peroxide scavenging activity of hydroalchoholic extract of Citrullus lanatus seeds was found to be 290µg/ml. The reducing capabilities of hydroalchoholic seed extract and Immunomodulatory activity by NBT assay was found to be in dose dependent manner. In-vitro studies may be helpful to understand the molecular mechanism of oxidation and to reveal phytochemicals of the extract responsible for showing antioxidant and immunomodulator activity. Citrullus lanatus seeds extract exhibited significant in-vitro antioxidant and Immunomodulatory activity.