Rapid declines in hospital admissions for acute myocardial infarction (AMI) following smoke-free ordinances have been reported in smaller communities. The AMI mortality rate among persons age 45 + years (deaths per 100,000 persons, age-standardized to the 2000 US population) in the 3 years before adoption of the smoke-free ordinance (the expected rate) was compared with the rate observed in the first full year after the ban (the target year) in six US states. Target-year declines were also compared to those in states without smoking bans. Target-year declines in AMI mortality in California (2.0%), Utah (7.7%) and Delaware (8.1%) were not significantly different from the expected declines (P = 0.16, 0.43 and 0.89, respectively). In South Dakota AMI mortality increased 8.9% in the target year (P = 0.007). Both a 9% decline in Florida and a 12% decline in New York in the 2004 target year exceeded the expected declines (P = 0.04 and P < 0.0002, respectively) but were not significantly different (P = 0.55 and 0.08, respectively) from the 9.8% decline that year in the 44 states without bans. Smoke-free ordinances provide a healthy indoor environment, but their implementation in six states had little or no immediate measurable effect on AMI mortality.