The objective of this study was to analyze the trends in prevalence, awareness, treatment and control of hypertension in the middle-aged population of China. There were about 1,000 participants each from 13 different study populations that were examined in surveys conducted from 1992-1994 (n=18,746) and in 1998 (n=13,504) in conjunction with the China Multi-Center Study of Cardiovascular Epidemiology. Half the subjects were men and half were women; their ages ranged from 35 to 59 years. Hypertension was defined as systolic blood pressure ≥ 140 mm Hg, diastolic blood pressure ≥90 mmHg, and/or current treatment with antihypertensive medications. Hypertension awareness and treatment were assessed with a standardized questionnaire. Hypertension control was defined as blood pressure measurements of less than 140/90 mmHg. The results showed that 24.0% of participants had hypertension in 1998, an increase of 2.3% from 1992-1994 (p<0.05). The prevalence of hypertension was 25.4% higher in urban than in rural areas, and was higher in men than in women. Among hypertensives, 42.6% were aware of their hypertension (a 5.3% increase compared with 1992-1994, p<0.05), 31.1% were treated (a 3.8% increase, p<0.05), and 6.0% were controlled (a 2.6% increase, p<0.05). The rates of awareness, treatment and control were higher in women than men, and higher in urban than rural areas. For treated hypertensives, the rate of control increased from 12.7% in 1992-1994 to 19.9% in 1998 (p<0.05). These findings indicate that hypertension prevalence is increasing in China. Control rates, while improving, still remain low. This implies that effective public health measures are needed to enhance the awareness, treatment, and control rates in the Chinese population.