Infestations of brown dog ticks (Rhipicephalus sanguineus) are difficult to control. This study aimed to evaluate the efficacy of phoxim and deltamethrin against R. sanguineus in vitro and in vivo. In vitro studies, the evaluation involved the exposure of R. sanguineus adults, nymphs, and larvae to phoxim (1 ml/1000 ml) and deltamethrin (1 ml/1000 ml) observations were recorded for 24 hours, and the eggs were assessed and compared with a negative control tick group that had been exposed to water for 14 days,  In vivo studies, twenty local dogs have been divided into four groups of five each: The 1st group was non-infested dogs; the 2nd group is infested untreated dogs; the 3rd group was infested dogs and treated with a therapeutic dose of phoxim; and 4th  group  was infested dogs and treated with a therapeutic dose of deltamethrin. Results revealed that phoxim was more effective than deltamethrin on adult of R. sanguineus, while deltamethrin appeared to be more effective than phoxim on nymphs and larvae of R. sanguineus. Both acaricides significantly inhibited egg hatchability of R. sanguineus with the same potency.