Respiration is a fundamental human body function that may provide use- ful information about the clinical status of a patient. Suitable and continuous monitoring of the Respiratory Rate (RR) is thus essential to promptly detect anomalies that may be signs of potentially harmful or life-threatening disorders. However, traditional RR mon- itoring systems consist of sensors and devices which are often expensive, invasive, and can be deployed only in hospital settings, requiring trained medical staff. In this chapter, an overview of alternative low-cost and non-invasive video-based methods for respiration monitoring is presented along with a brief review of earlier work. Principles underlying the extraction of relevant information content from video signals are described and spe- cific video-based solutions for newborn and adult monitoring are presented. Modelling and simulation of breathing patterns is also addressed. The performance of the proposed solutions is finally discussed also on the basis of experimental results.