Biomechatronic design methodology is discussed for the design of monitoring and sensor systems for biotechnological processes. The bioprocess monitoring systems are examples of complex biomechatronic systems between electronic, mechanical, and biological subsystems, and where in particular the biological parts, through active microbial or cellular components, influence the design solutions in a complex manner. The biomechatronic approach facilitates configuration of the monitoring and sensor systems with production and quality needs in focus, and can by that lead to more efficient design solutions.