We begin by detailing methods for tracking using active contour, which has been very successful in biomedical applications. Starting with the basic Bayesian model, we describe the tracking method and the conventional Kalman filter that uses a centroid and correlation measurements for target detection. A prominent event of this book is the introduction of particles recently emerged filter, which promises to solve the tracking problem previously resolved by conventional means. Other unique features of Biomedical Image Analysis: Tracking is an explanation of biomedical image analysis-based method.