A seroprevalence study of canine leishmaniasis was carried out in five provinces in northern Morocco: Taounate, Al Hoceima, Zouagha Moulay Yacoub, Chefchaouen and Ouezzane. 55 localities have been concerned and a total of 1,013 dogs were screened, which represents almost 100% of the canine census. Of the screened dogs: 87 showed antibody titer > or = 100 when tested by IFAT (seroprevalence of 8.6%) and were distributed in 83 asymptomatics (without clinical symptoms) and four symptomatics (with one or several symptoms of leishmaniasis) with important variations according to the locality. Relative frequency of asymptomatic dogs was observed (8.2%), and the seroprevalence increased in middle altitude (500 m < altitude < 1,000 m) and high altitude (> or = 1,000 m). Parasites isolated from dogs were identified as L. infantum MON-1 by isoenzyme profile and Rsal digestion.