Abstract. We present a markerless real-time, model-based 3D face tracking methodology. The system combines two robust and complimentary optimization-based strategies, namely active contours and mutual information template matching, in order to obtain real-time performances for full 6dof tracking. First, robust head contour estimation is realized by means of the Contracting Curve Density algorithm, effectively employing local color statistics separation for contour shape optimization. Afterwards, the 3D face template is robustly matched to the underlying image, through fast mutual information optimization. Off-line model building is done using a fast modeling procedure, providing a unique appearance model for each user. Re-initialization criteria are employed in order to obtain a complete and autonomous tracking system. Key words: Real-time Face Tracking, Nonlinear Optimization, 3D Template Matching, Mutual Information, Active Contours, Local Statistics Contour Matching, 3D Face Model...