Process plant operators often have to respond to many alarms. Nuisance alarms often clutter and obscure an operator's view of critical and important information, with potentially severe consequences. The Intelligent Alarm Management System suppresses nuisance alarms and provides valuable advisory information to help operators quickly focus on important alarm information and take correct actions. This system has been implemented on Yokogawa distributed control systems, validated in real online tests, and accepted by plant operators. The results show that nuisance alarms are effectively suppressed and alarm systems become more helpful.