BACKGROUND: Canine brucellosis may occur due to Brucella spp. other than Brucella canis. Brucella bacterium is transferred between dogs, ruminants, and humans. Therefore, there is a need for vaccinating the hosts of Brucella, especially dogs. OBJECTIVES: The present study evaluates the efficacy of Rev.1 against B. melitensis in experimentally infected dogs. METHODS: Twelve Brucella-negative dogs were divided into two groups of test and control. The animals in the experimental group were vaccinated with Rev.1. After vaccination, sera of the dogs were tested by the standard tube agglutination test (STAT) and Rose Bengal test (RBT). Five months following vaccination, dogs in both groups were inoculated with 3×109 CFU of B. melitensis biotype 1. Serum samples were taken after inoculating the bacteria and were examined using the STAT and RBT. The specimens of lymph nodes and reticuloendothelial organs were collected for bacteriological culture. RESULTS: After the inoculation of Brucella, the antibody titer was significantly higher in the control dogs than in the experimental group. B. melitensis biotype 1 was isolated from all the control dogs, but it was isolated from three dogs in the test group. CONCLUSIONS: According to the findings of the current study, we recommend further studies on the immuniza-tion of dogs with the Rev.1 vaccine along with vaccinating small ruminants.