Abnormal respiratory rate is a marker of serious illness, yet hospital based research shows that respiratory rate is under-reported when compared to others vital signs. Measuring respiratory rate frequently and communicating abnormalities in respiratory rate parameters, has the potential to reduce morbidity and mortality in hospitalized patients. This book discusses the work related to the reliability and validity of three novel methods for counting breaths by using a mobile phone application. A simple mobile phone application could be used as a powerful tool to effectively count and monitor respiratory rate.