130 Background: Four immune checkpoint inhibitors have been FDA approved from 2011 to 2016. Immune checkpoint inhibitors function differently from chemotherapy and have different benchmarks for response as well as different side effect profiles. This report examines how oncologists in two large medical groups have introduced these new treatments into their practices. Kaiser Permanente is a large HMO which insures 8.5 million members in the state of California and has an exclusive contract with 2 large medical groups to care for its members. There are over 200 medical oncologists caring for KP members practice at over 35 medical centers. The care of the KP members has been documented in an EPIC based medical record systems since 2006. Methods: The Pharmacy Research Outcomes Group has conducted a retrospective cohort study looking at patients who initiated Checkpoint inhibitors between March 2011 and September 2016 for this review and followed the patients till December 2016. Electronically available data collected for this review includes patient characteristics such as but not exclusive to: cancer diagnosis, previous therapies, current therapies, age, sex, ethnicity, immune related adverse events (IRAEs) proxy by diagnosis code, duration of immunotherapy, use of systemic steroids, Charlson Co-morbity Index and survival. Results: We reviewed a total of 1760 users of Checkpoint Inhibitors. We show the uptake of this class of medications aligns with approved checkpoint inhibitors and the new indications of these agents. We were able to electronically pull medical information and define IRAEs. Our data closely matches the expected incidence of IRAEs as reported in clinical trials. We were also able to monitor the use of steroids in response to these events. Conclusions: The ability to collect and track this information has allowed the group to better understand patient selection practices as well as management practices in the community practice setting.