Objective: To formulate nanoemulsion from essential oils of Mentha (M.) piperita L. and Eucalyptus (E.) globulus L. and to compare their repellant activity with normal essential oils and N,N-diethyl-m toluamide (DEET) as a standard chemical compound. Methods: In this study, protection time of essential oils and DEET was evaluated on four human subjects using test cage, and their values were determined against Anopheles stephensi. Furthermore, ED50 values for the above essential oils were determined using the ASTM E951-94 method. The compositions of essential oils were determined using GC-MS, and droplet size and zeta potential of the nanoemulsion were measured with dynamic light scattering. Results: The results (expressed as mean±SD) showed that protection time of M. piperita 50％, M. piperita Nano 50％, E. globulus 50％, E. globulus Nano 50％, and DEET 25％ was (2.89±0.45) h, (4.17±0.28) h, (0.96±0.27) h, (5.51±0.02) h, and (6.10±0.47) h, respectively. ED50 values were 29.10 (95％ CI: 23.36-36.06) μg/cm2 for Mentha, 19.39 (15.35-23.99) μg/cm2 for Mentha Nano, 36.10 (28.70-48.01) μg/cm2 for Eucalyptus, 18.50 (14.65-23.23) μg/cm2 for Eucalyptus Nano, and 3.62 (2.68-4.55) μg/cm2 for DEET, respectively. E. globulus Nano and M. piperita Nano provided significantly longer protection than normal essential oils E. globulus and M. piperita (P<0.01). Conclusions: The preparation of nanoemulsion from the essential oils of M. piperita and E. globulus, significantly increases the protection time and reduces ED50 values of these essential oils, hence, M. piperita Nano and E. globulus Nano can be good altatives to DEET and other chemical compounds.