The main objective of this study was to find the optimal dosage of deltamethrin, cyphenothrin, d-tetramethrin, and tetramethrin that would elicit repellency and irritability responses of Aedes aegypti. The F1-F3 generations of field mosquitoes collected from Pu Teuy Village, Sai-Yok District, Kanchanaburi Province, Thailand, were tested with four pyrethroids to determine the LC₂₅, LC₅₀, and LC₉₉. These concentrations were 0.010%, 0.020%, and 0.055%, respectively, for deltamethrin; 0.113%, 0.167%, and 0.353%, respectively, for cyphenothrin; 2.091%, 2.770%, and 5.114%, respectively, for d-tetramethrin; and 2.377%, 4.251%, and 10.715%, respectively, for tetramethrin. All dosages were tested in the excitorepellency system. Survival analysis was used to compare each chamber of the test. It was found that cyphenothrin had a stronger repellent effect than the other pyrethroids, while the contact irritant effect was similar among compounds tested. The LC₅₀ of each pyrethroid was found to be the optimal dose for repelling Ae. aegypti. There was no significant difference in LC₉₉ values for either non-contact or contact trials for each pyrethroid.