Indonesia is the country with the highest cases of dengue fever in Southeast Asia. The WHO estimates a 50–100 million dengue infections worldwide every year. Dengue Hemorrhagic Fever (DHF) is transmitted through the bite of female Aedes mosquitoes infected with the Dengue virus. Mosquitoes Aedes aegypti is the main vector of the dengue virus. At the time, there is no cure for dengue so that the control efforts are focused on breaking the chain of life cycles. One effort to prevent the transmission of the dengue virus is to avoid vector mosquito bites. Repellent can reduce exposure to the bite of mosquitoes infected with the dengue virus. The aim of this study was to determine the effectiveness of the extract of citrus hystrix leaf as a repellent against the Aedes aegypti mosquitoes. This research is a laboratory experimental study with a one-shot case study design. In this study, the extract of citrus hystrix solution was made at a concentration of 10%, 20%, and 30%, and then the extract solution was used as a stock to make a 100-gram base lotion that would be used as a repellent. Repellent effectiveness is seen from the percentage of repellent protection power. The percentage of repellant protection used with the basic ingredients of Citrus hystrix leaf extract at concentrations of 10%, 20%, and 30%, respectively, at 93.33% 94.67%, and 97.33%. The extract of citrus hystrix leaf was found to be effective as a repellent against Aedes aegypti mosquitoes.