The agents that cause diseases of zoonotic importance in canines, such as Canine brucellosis and Leptospirosis, have gained importance in human clinical practice. Objective: To discover the prevalence and behavior of both diseases in the canine population in the city of Medellin to develop measures of prevention and control in this area. Methods: A total of 1,300 canines were sampled to test for Brucella canis and Leptospira spp. using the PARP-2ME and MAT techniques, respectively, to establish the statistical significance of the different variables analyzed (P ≤ 0.05; OR ≥ 1; 95% CI). Results: Seroprevalence was determined to be 7.32% for B. canis and 9.08%, for Leptospira spp. with a 0.77% co-infection rate of both diseases. The most prevalent serovars for Leptospira spp. were Canicola (3.38%), Icterohaemorrhagiae (2.62%), and Pomona (0.92%). A statistical association was reported for B. canis with the commune variable (San Javier P = 0.002; OR = 2.724 / Guayabal P = 0.000; OR = 3.862 / Belen P = 0.002; OR = 2.953), and for Leptospira spp. with the commune variable (Buenos Aires P = 0.011; OR = 2.220) and age (37-48 months P = 0.005; OR = 4.272). Conclusions: This study shows that both agents are in circulation among the canine population in the city and in all the communes analyzed, representing a possible risk of infection to owners and other animals entering into contact with them.