Recent recogfigurable nulti-sensor readout intergrated circuits (ROIC) and systems for heterogeneous monitoring applications are presented, which are mostly focused for healthcate and environmental applications. For healthcare monitoring, physiological sensing interfaces for wearable devices and display-based systems are developed including its reconfigurable ROIC and wireless connectivity. For achieving low-power and miniaturized characteristics in wearable device, most post-processing burdens are migrated from sensor modules to smartphones. The core feature of environmental interfaces is to detect hazardous gases, which include temperature and humidity sensors to compensate for various sensor device deviations. For good sensitivy with low-noise characteristics, various circuit-level techniques such as correlated double sampling, chopper stabilization, and impedance boosting are selectively adopted, and analog-to-digital converters are somtimes integrated into ROICs to minimize possible noise-coupling paths. Another recent noticeable trends are heterogeneous sensor interfaces to integrate different kinds of sensors for multiple application, and their system prototypes for display-based systems and automotive electronic are shown to provide new conbined service capabilities.