Examined predictors of smoking cessation attempts and predictors of the outcome of those attempts after the introduction of a workplace smoking ban. Smokers were surveyed in the month before the ban came into force, and variables collected at that time were used to predict outcomes 6 months later. Data from 491 respondents who were smokers at the time of the initial survey were used, and a set of potential predictor variables was chosen on both theoretical and empirical grounds. Making a cessation attempt was predicted by the strength of desire to quit and, to less extent, by not having been subject to extensive restrictions on smoking before the mandated ban, having tried to quit before, perceiving oneself high in ability to quit, and being worried about smoke at work. For the outcome of cessation attempts among those who tried, success was best predicted by low levels of a composite habit strength variable and, to less extent, by desire to quit, no previous attempts to quit, the existence of social supports for quitting, and educational status. Although cognitive variables were important in predicting attempts, they played only a minor role in predicting maintenance. Behavioral and environmental variables contributed slightly to prediction of attempts and strongly to prediction of maintenance.