A detailed description of the fine structure of Balantidium ctenopharyngodoni Chen, 1955 with an emphasis on its vestibulum is given in the present paper. As to the vestibular kinetids, special attention is paid to the characters of T1, T2 microtubules and nematodesmata. Serving as the major skeleton to the vestibular cortex, the T1, T2 and Pc microtubules are described herein and their support function is also discussed. Moreover, the well-developed nematodesmata of the vestibular kinetids that form a large basket-like complex are described in detail.