Adoption of the applied surface-backpressure types of managed pressure drilling (MPD) technologies in deepwater have mainly involved the use of a rotating control device (RCD). The RCD creates a closed drilling system in which the flow out of the well is diverted towards an automated MPD choke manifold (with a high-resolution mass flow meter) that aside from regulating backpressure also increases sensitivity and reduces reaction time to kicks, losses, and other unwanted drilling events. This integration of MPD equipment into floating drilling rigs to provide them with MPD capabilities, including the capacity to perform pressurized mud cap drilling (PMCD) and riser gas mitigation (RGM), has produced improvements not only in drillability and efficiency, but most importantly in process safety. Case histories on how MPD has performed will be presented on the following: • allowed drilling to reach target depth in rank wildcat deepwater wells that have formations prone to severe circulation losses and narrow mud weight windows; • increased drilling efficiency by minimizing non-productive time associated with downhole pressure-related problems and by allowing for the setting of deeper casing seats; • enhanced operational and process safety by allowing for immediate detection of kicks, losses and other critical downhole events. • provided riser gas mitigation capabilities that can detect a gas influx once it enters the drilling fluid stream, and not after it has already broken out above the rig blow-out preventers (BOPs).