This study evaluated the efficacy and safety of medi- cal shampoo containing terbinafine hydrochloride and chlorhexidine gluconate in dogs with dermatophytos is complicated with bacterial infection. Although several stud- ies in dogs and cats with fungal dermatitis have found that oral administration of terbinafine is effective for controlling clinical signs, the topical form of terbinafine has rarely been studied in dogs and cats. Therefore, this study evaluated the efficacy of medical shampoo containing terbinafine hy- drochloride and chlorhexidine gluconate in dogs with der- matophytos is complicated with bacterial infection. Eight dogs infected with Microsporum spp. complicated with bacterial infection were enrolled in this study. These dogs were further blindly divided into Group 1 (no treatment, fourdogs) and group 2 (treated with medical shampoo with terbinafine/chlorhexidine, four dogs). Clinical improvement was evaluated using bacterial and fungal cultural evaluation combined with clinical evaluation. This study found that the medical shampoo has sufficient efficacy to treat varying degrees of dermatophytosis complicated with bacterial in- fection in dogs, although the speed of improvement differed according to the degree and type of infection. Our study also found that combined therapy using antifungal and antibac- terial agents can improve clinical signs more effectively and rapidly, suggesting that concurrent bacterial infection plays a significant role in the development of dermatitis.