Background: Although the relationship between body weight and blood pressure (BP) is well established, there is a lack of data regarding the impact of obesity on the prevalence of hypertension in primary care practice. The objective of this study was to assess the prevalence of hypertension and the diagnosis, treatment status, and control rates of hypertension in obese patients as compared to patients with normal weight. Methods: A cross-sectional point prevalence study of 45,125 unselected consecutive primary care attendees was conducted in a representative nationwide sample of 1912 primary care physicians in Germany (HYDRA). Results: Blood pressure levels were consistently higher in obese patients. Overall prevalence of hypertension (blood pressure ≥140/90 mm Hg or on antihypertensive medication) in normal weight patients was 34.3%, in overweight participants 60.6%, in grade 1 obesity 72.9%, in grade 2 obesity 77.1%, and in grade 3 obesity 74.1%. The odds ratio (OR) for good BP control (<140/90 mm Hg) in diagnosed and treated patients was 0.8 (95% confidence interval [CI] 0.7– 0.9) in overweight patients, 0.6 (95% CI 0.6–0.7) in grade 1, 0.5 (95% CI 0.4–0.6) in grade 2, and 0.7 (95% CI 0.5– 0.9) in grade 3 obese patients. Conclusions: The increasing prevalence of hypertension in obese patients and the low control rates in overweight and obese patients document the challenge that hypertension control in obese patients imposes on the primary care physician. These results highlight the need for specific evidence-based guidelines for the pharmacologic management of obesity-related hypertension in primary practice.