In this paper, an approach is proposed to the fault detection in multirate sampled-data (MSD) systems with multiple time-delays in both input and output channels. The background of our study is the increasing demands for fault detection in complex, distributed process control systems, where the plant, controllers, sensors and actuators are networked by standardized bus systems. The core of the approach proposed is a) to derive parity relations of the MSD system with time-delays while taking the different sampling rates and time-delays into account; b) to take the intersample behaviour of the continuous-time disturbances and faults into consideration with the help of operators.