In this document we present an agent for people detection and tracking through stereo vision. The agent makes use of the active vision to perform the people tracking with a robotic head on which the vision system is installed. Initially, a map of the surrounding environment is created including its motionless characteristics. This map will be later on used to detect objects in motion and to search among them people by using a face detector. Once a person has been spotted, the agent is capable of tracking them through the robotic head that allows the stereo system to rotate. In order to achieve a robust tracking we have used the Kalman filter. The agent focuses on the person at all times by framing their head and arms on the image. This task could be used by other agents that might need to analyze gestures and expressions of potential application users in order to facilitate the robot-human interaction.