A field survey was conducted to evaluate susceptibility of Rhipicephalus (Boophilus) annultusto commercial deltamethrin 5% on different localities in Beni-suef province using different bioassays (Adult immersion test AIT, Larval Packet test LPT and Esterase test). Two concentrations of deltamethrin 5% (200 and 400 ppm) were tested for their acaricidal efficacy against adult R. (B.) annulatus collected from different localities. Adult tick mortality at 400 ppm was higher than 200ppm and the survived females' oviposited with complete eclosion blocking for eggs. While 200 ppm allowed eggs to hatch in all populations. The larval packet test was used to evaluate the larval mortality at six deltamethrin concentrations (0.000625, 0.00125, 0.0025, 0.005, 0.010 and 0.020). Lethal concentrations (LC50– LC90), confidence intervals (CI) and slope (S) were estimated by probit analysis and the highest LC50 appeared in Ehanasia locality (0.01) but the lowest LC50appeared in Alfashin (0.0006). Esterase assay with substerate α naphthylacetate applied on R. (B.) annulatus larvae and mean enzyme activity was determined; Ehnsaia locality appeared with the highest activity 2.373±0.058 while Alfashin was the lowest 1.024±0.014. From the results of this work, it was concluded that one tick population of the investigated locations was of possible susceptible, one of possible tolerant and one resistant to deltamethrin. The data generated on deltamethrin resistance status will help in formulating tick control strategy in the region.