This study reports the experimental transmission of Borrelia anserina to domestic chickens by infected Argas (Persicargas) miniatus. Clinical alterations as well as prepatent and patent periods were evaluated. Twenty-seven 67-day-old birds were divided into three groups in a randomized experimental design. The first group was exposed to ticks infected with B. anserina, the second group was exposed to noninfected ticks, and the third group was not exposed to ticks. Blood smears from each bird of groups 1 and 2 were prepared daily and examined for 25 days postexposure (PE). Examination of the blood smears from birds in group 1 revealed large numbers of spirochetes from days 5 to 12 PE. In this group the prepatent and patent periods were 5-7 and 4-7 days, respectively. Birds from group 1 presented ruffled feathers, pale combs, drowsiness, inappetence, loss of weight, and greenish diarrhea after day 6 PE. The current study confirms the viability of experimental transmission of B. anserina to domestic chickens by A. (P.) miniatus.