Concerns have been raised frequently about caffeine's potential for increasing blood pressure (BP) and posing a risk for cardiovascular disease. This review surveys research concerning the effects of caffeine on BP and heart rate (HR). Tolerance to caffeine, family history of hypertension, borderline hypertension, and hypertension are also examined as potential moderators. Results from epidemiological studies are inconsistent. Experimental laboratory studies have generally found that caffeine produces acute rises in systolic and diastolic BP that are additive to any stress-induced increases. Synergistic effects which might pose a more serious risk are rarely found. Heart rate data are less consistent, possibly due to the different ways HR is measured. Tolerance to the cardiovascular effects of caffeine has reliably been reported; however, overnight abstinence may be sufficient to negate tolerance effects to most levels of caffeine ingestion in typical caffeine users. Though caffeine drinkers may exhibit acute increases in BP, the long-term effects appear to be minimal. However, persons at risk for hypertension may be more vulnerable to the BP effects of caffeine.