More than 30 million American workers 17 years of age or older have some degree of hypertension, and nearly two-thirds of these workers have blood pressure greater than 160/95 mm Hg. Many employer-sponsored hypertension detection and control programs have been reported, but much of the information about these programs is anecdotal and based on perceptions rather than on formal evaluation. To gain an estimate of the number and nature of such programs among California employers, the authors surveyed 424 California organizations with more than 100 employees at one or more sites. Experienced survey researchers conducted 30-minute telephone interviews with key personnel of these firms to probe their companies' health promotion activities, including those devoted to hypertension screening and control. Of the 424 organizations, 43 (10.1 percent) had worksite hypertension programs, and 24 (5.7 percent) were planning to initiate such a program within the following 12 months. But 357 employers neither offered a hypertension program at the time of the survey nor planned to initiate one within the following year. Survey responses indicated that during the 3 years before the survey, the number of worksite hypertension programs among the organizations surveyed had increased by 110 percent. This rapid rate of increase, together with the nearly 50 percent increase in number of programs that employers were planning for the following 12 months, suggest that the number of similar programs in other regions may also be growing at an accelerating rate. The National Heart, Lung, and Blood Institute's strong endorsement of worksite hypertension programs and employers' current interest in health promotion and disease prevention activities should act as a spur for further growth of these programs. For maximum growth, however--especially among smaller companies--active promotion by business and community groups is essential.