Introduction: The 2017 American College of Cardiology/American Heart Association (ACC/AHA) blood pressure (BP) guideline uses lower clinic and out-of-clinic BP thresholds to define hypertension compared to previous US guidelines. Using these thresholds, we determined the associations between white coat hypertension (WCH) and masked hypertension with cardiovascular disease (CVD) events and mortality. Methods: We included 993 African Americans participating in the Jackson Heart Study who had clinic BP measured during their baseline study visit between 2000 and 2004 and underwent ambulatory blood pressure monitoring (ABPM). We defined normotension, WCH/white coat effect (WCE), masked/masked uncontrolled hypertension, and sustained hypertension using clinic BP and mean awake BP on ABPM (Table). CVD events (i.e., coronary heart disease and stroke; n=107), and all-cause mortality (n=185) were adjudicated from baseline through December 2014 and December 2016, respectively. Results: The mean age of participants was 59 years and 68% were female. Among those not taking antihypertensive medication, 38% had normotension, 27% had WCH, 33% had masked hypertension, and 31% had sustained hypertension. WCH, masked hypertension, and sustained hypertension were each associated with an increased risk for CVD and mortality compared to normotension (Table). Among those taking antihypertensive medication, 26% had controlled normotension, 25% had a WCE, 45% had masked uncontrolled hypertension, and 39% had treated sustained hypertension. Masked uncontrolled hypertension was associated with a higher risk for CVD and a lower risk for mortality compared to controlled normotension. WCE was not associated with CVD events or all-cause mortality. Conclusions: According to the ACC/AHA BP guideline, WCH and masked hypertension are common among African American adults. ABPM could have an important role in guiding antihypertensive medication initiation and intensification to reduce CVD and mortality risk among African Americans.