This paper presents an interactive bowling system using vison-based tracking for AR. With the bowling system, a user can enjoy the bowling game by rolling a real ball down a bowling lane model placed on a tabletop in the real world. On the lane model, there are virtual pins generated with CG. The virtual pins are overlaid onto the input images, which are captured by a web-camera attached to a hand-held tablet PC, according to the camera motion. The camera motion is estimated by multiple 2D markers which are also placed on the tabletop around the lane model. The lane and the ball are also tracked by vision-based tracking. According to the detected ball's trajectory on the lane, the geometrical relationship between the real ball and the virtual pins is computed to judge whether the ball is touching any pins or not. After judging, the pins touching the ball are knocked down. Our vision-based tracking method can run in real-time, so it can also be applied to other interactive applications.