This paper descibes the implementation of an integrated monitoring system for a CNC machine tool and its machining processes such as drilling, milling, turning and grinding. The monitoring system uses a variety of sensors such as force, torque, vibration, acoustic emission, and temperature to monitor the machining processes and the physical conditions of the machine tool. The major aim is to improve the reliability of the machining operations and machine condition so as to ensure high part quality and reduce inspection costs. The paper describes the integrated monitoring systems developed and a case study to describe some of the obtained results.