Abstract—Essential hypertension is the most common diagnosis in US primary care settings for middle-aged persons and seniors. Yet, data on hypertension screening, treatment, and control in such settings are limited. We analyzed National Ambulatory Medical Care Survey data to examine the rates of and factors associated with hypertension screening, treatment, and control during US office visits in 2003 and 2004. Blood pressure was measured in 56% (95% confidence limits: 52% to 59%) of all visits by patients 18 years of age and in 93% (95% confidence limits: 89% to 96%) of hypertensive patient visits. Among the latter, 62% (95% confidence limits: 55% to 69%) were treated. Diuretics were the most commonly prescribed antihypertensive agents (46%; 95% confidence limits: 41% to 50%), and combination therapy was reported in 58% (95% confidence limits: 54% to 63%) of treated visits. Only 39% (95% confidence limits: 34% to 43%) of treated visits were at recommended blood pressure goals. The odds of not being screened for hypertension were notably greater for visits with a provider other than a primary care physician or cardiologist (10.0; 95% confidence limits: 5.5 to 16.7) and for nonwell care visits (5.6; 95% confidence limits: 3.6 to 8.3). Greater odds of not being treated for hypertension were noted by geographic region (South versus Northeast: 2.6; 95% confidence limits: 1.2 to 5.6) and visit type (first time versus return visits; 1.6; 95% confidence limits: 1.1 to 2.4). The odds of not having blood pressure controlled were greater for patients with comorbidities (1.6; 95% confidence limits: 1.1 to 2.4). In conclusion, more intervention efforts are needed to further reduce the gaps and variations in routine practice in relation to evidence-based practice guidelines for hypertension screening, treatment, and control.