The word 'mechatronics' provides a focus for the integration of electronic hardware and computer software with mechanical engineering in a product or process. Sensors and sensing systems are integral to the functioning of mechatronic systems as providers of the process and procedural data on which their operation is based. In particular, development of digital control systems has been supported by increases in performance, reducing real costs, of the associated electronic processing, which has led to development of dedicated controller architectures based on use of application-specific integrated circuits. In the area of sensor development, the driving force is the silicon-based technology that can provide both the signal processing element in the form of the integrated circuit but increasingly also the sensing component, often on the same chip. Additionally, development of the techniques of micromachining has enabled production of complex structures on a chip, some of which, when combined with on-chip sensing and processing, may be considered to be mechatronic in their own right. The paper therefore reviews the role and importance of sensors and measurement systems within mechatronics and illustrates this with examples drawn from manufacturing, vehicle systems and domestic products.