Primary borreliosis is exceptional in North Africa. From 1988 to 1992, we observed 23 cases (10 females, 13 males; age 20-67 years) of erythema chronicum migrans in our unit. The lesions began during the months of April to October with a peak in July and August. There was always an unique characteristic lesion with a central mark left by the bite in 20 cases. Serological studies were not performed. Several antibiotics were given. Primary borreliosis of the erythema chronicum migrans type are seen in Tunisia and probable throughout North Africa. The clinical presentations and seasonal distribution are the same as in Europe.