As wireless and mobile technologies have advanced significantly, lots of large sized healthcare organizations have implemented so called mobile hospital (m-Hospital) which provides a location independent and point of care (POC) clinical environment. Implementation of m-Hospital enhances quality of care because health professionals such as physicians and nurses can use hospital information systems at the very place where patients are located without any delay. This paper presents a real-time patient monitoring system based on wireless network technologies. A general framework for the patient monitoring process is introduced and the architecture and components of the proposed monitoring system is described. The system collects and analyzes biometric signals of in-patients who suffer from cancer. Specifically, it continuously monitors oxygen saturation of patients in bed and alarms health professionals instantly when an abnormal status of the patient is detected. The monitoring system has been used and clinically verified in a university hospital.