A multichannel fiber-optic combustion pressure sensor system is described dedicated to parametric emission monitoring systems (PEMS) for use in natural gas-fueled, stationary, and reciprocating engines. In view of the emerging 1995 emission regulations for large stationary engines, the natural gas pipeline operators have turned their attention to PEMS' for predicting and controlling the amount of polluting emissions such as NOx and HC. We present design considerations and performance data of a 8-channel pressure monitoring system employing fiber-optic combustion pressure sensors. The control/monitoring unit offers capabilities of sensor calibration, health monitoring, and real-time data acquisition. Using an engine position sensor trigger, the monitoring unit can calculate peak pressure, indicative mean pressure, and location of peak pressure. The system allows for 50 kHz, burst mode transfer of multisensor data to a host PC. We demonstrated performance data collected on three large-bore engines and long-term endurance test data. While initially intended for stationary engines, the system can be used in applications requiring portability including moving vehicles.