PURPOSE: This study explored the environmental and psychological correlates of active commuting in a sample of adults from the European Prospective Investigation into Cancer Norfolk cohort. METHODS: Members of the cohort who were in employment, lived within 10 km of work, and did not report a limitation that precluded walking were included in this analysis. Psychological factors, perceptions of the neighborhood environment and travel mode to work were reported using questionnaires. Neighborhood and route environmental characteristics were estimated objectively using a geographical information system. The mediating effects of psychological factors were assessed using a series of regression models. RESULTS: A total of 1279 adults (mean age = 60.4 yr, SD = 5.4 yr) were included in this analysis, of whom 25% actively commuted to work. In multivariable regression analyses, those who reported strong habits for walking or cycling were more likely to actively commute, whereas those living 4-10 km from work were less likely to actively commute. In addition, living in a rural area was associated with a decreased likelihood of men's active commuting, and in women, living in a neighborhood with high road density and having a route to work that was not on a main or secondary road was associated with an increased likelihood of active commuting. There was weak evidence that habit acted to partly mediate the associations between environmental correlates and active commuting in both sexes. CONCLUSIONS: The findings suggest that interventions designed to encourage the development of habitual behaviors for active commuting may be effective, especially among those living close to work.