Purpose. To identify the organizational and professional correlates of the integration of the ecological approach in Canadian public health organizations' tobacco control programs for youth. Design. Cross-sectional survey. Setting. Canadian public health organizations. Subjects. One hundred and ten tobacco control programs implemented in 90 organizations. The response rate for the organizations was 87%. Measures. Descriptions of programs were obtained by telephone interviews. An analytical procedure was applied to the program data to identify intervention settings, targets and strategies for each program. Using this information, a summary score of the integration of the ecological approach was estimated for each program. Organizational and professional variables were assessed by self-administered questionnaires to managers and professionals involved in these programs. Results. The level of integration of the ecological approach in programs was related to organizational (frequency of contacts and collaborations with external partners, team composition) and extraorganizational factors (size of the city in which the public health unit is located). Cognitive attributes of the practitioners (knowledge and beliefs) also emerged as significant predictors. Finally, positive associations were observed between practitioners' personal characteristics (educational achievement, working status in health promotion [full vs. part-time], previous experience, gender, and disciplinary/professional background) and cognitive predictors. Conclusions. Organizational environment and staff preparation play a critical role in the adoption of the ecological approach in tobacco control programs.