A Cochrane review included 77 studies (repeated before and after cross-sectional and cohort studies). Thirty-six studies used an interrupted time series study design, 23 studies use a controlled before-and-after design and 18 studies are before-and-after studies with no control group; six of these studies use a cohort design. Seventy-two studies reported health outcomes, including cardiovascular (44), respiratory (21), and perinatal outcomes (7). Eleven studies reported national mortality rates for smoking-related diseases. A number of the studies report multiple health outcomes. There is consistent evidence of a positive impact of national smoking bans on improving cardiovascular health outcomes, and reducing mortality for associated smoking-related illnesses. Effects on respiratory and perinatal health were less consistent. We found 24 studies evaluating the impact of national smoke-free legislation on smoking behaviour. Evidence of an impact of legislative bans on smoking prevalence and tobacco consumption is inconsistent, with some studies not detecting additional long-term change in existing trends in prevalence.