Introduction: High blood pressure is a major risk factor for cardiovascular disease and a key public health concern. In Quebec, several data sources are available to assess its prevalence, and the objective of this study is to compare them. Methods: Changes in hypertension between 2000–2001 and 2010–2011 were analyzed using linked medical-administrative data from the Integrated Chronic Disease Surveillance System of Quebec (Sismacq) and self-reported data from the Canadian Community Health Survey (CCHS) among Quebecers aged 20 to 79. The prevalence in 2009 is compared with data from the Canadian Health Measures Survey (CHMS). Results: In 2009, the prevalence based on medical-administrative data, estimated at 20.6% [95% CI: 20.5–20.6], was similar to that measured or treated, at 22.6% [95% CI: 20.3–24.8], but slightly higher than the self-reported prevalence, 18.0% [95% CI: 16.9–19.1]. The greatest difference was observed among people aged 65 to 79, particularly men. Both Sismacq and ESCC data indicate an increase in prevalence between 2000–2001 and 2010–2011. Conclusion: The prevalence of hypertension estimated using medical-administrative data is similar to that obtained using survey data combining blood pressure measurements with medication use. (R.A.)