Healthcare and other professionals can play a role in mobilizing communities to promote health, drawing upon their knowledge of the determinants of health and their power as leaders in the community. Two possible roles are suggested by the International Union of Health Promotion and Education (2000): mobilization of communities to create healthy environments, and various forms of advocacy. The Healthy Communities/Healthy Cities movement worldwide provides a good example of the former strategy (Ashton 1992). The evidence for the effectiveness of the Healthy Communities initiative in Canada demonstrates that its value lies in its ability to involve multiple partners at the community level to build a shared vision, seek consensus and take action on local concerns.