In experimental research, progesterone has been found to be beneficial to the central nervous and cardiovascular systems; however, its potential role in preventing atherosclerosis in elderly men remains unclear. In this prospective study, we analyzed data in 385 older men and women from 6 communities in Beijing, China, in order to discover whether progesterone is associated with carotid intima-media thickness and plaque occurrence. Intima-media thickness and atherosclerotic plaques were determined by use of ultrasonography. Sex-hormone levels were measured by immunoassay. The data were analyzed via analysis of covariance and logistic regression analysis; P < 0.05 was considered statistically significant. We found a negative association between mean intima-media thickness and progesterone concentration in men, before and after adjustments for such traditional risk factors of atherosclerosis as age, triglyceride levels, total and low-density lipoprotein cholesterol levels, high-sensitivity C-reactive protein, systolic blood pressure, waist-to-hip ratio, and body mass index (analysis of covariance, P = 0.007 and P = 0.015, respectively). However, no such association was found in women (P = 0.304 and P = 0.247, respectively). In the logistic regression model that was adjusted for the confounding factors of atherosclerosis, men with progesterone levels in the lowest quartile (<1.87 nmol/L) had more risk of higher intima-media thickness (odds ratio, 2.15; P = 0.042). Although further experimental and prospective studies are warranted in order to determine the mechanism of progesterone's function in atherosclerosis prevention, we conclude that progesterone concentrations are negatively associated with carotid artery atherosclerosis in northern Chinese men 60 years of age or older.