The objective of this study was to determine the therapeutic and residual efficacy of a topically applied combination of cyphenothrin (40 %) and pyriproxyfen (2 %) against the tick Haemaphysalis elliptica and the flea Ctenocephalides felis on dogs. Twelve dogs were infested with 50 ticks 2 days before they were treated and with approximately 100 fleas 6 days before treatment and again 2 days before treatment and with 50 ticks and approximately 100 fleas at weekly intervals thereafter. They were ranked according to their flea counts and sex 5 days before treatment and randomly allocated to an untreated control group of 6 dogs and a treated group of 6 dogs. Ticks and fleas were collected from the dogs 48 h after treatment and 48 h after each infestation and live and dead ticks and live fleas were counted. The counts of ticks and fleas were transformed to geometric means, and efficacy was calculated by comparing these means. The product had a therapeutic efficacy of 83.1 % against H. elliptica and 97.5 % against C. felis 2 days after treatment. The residual period of protection during which efficacy was ≥ 90 % was 5 weeks for both H. elliptica and C. felis.