This experiment investigated three levels of threat in cigarette warning labels: no warning/text warning only/text + graphic warning. Teenagers in Canada and the US were exposed to one of these labels in a web-surfing environment. Participants surfed a website sponsored by a familiar cigarette brand or an unfamiliar cigarette brand. After surfing, three dependent measures were assessed: brand attitude, website attitude, and smoking intent. Results indicated that the graphic label was the most effective for Canadian participants, leading to negative attitudes and lower smoking intentions, but the graphic label was least effective at lowering smoking intentions for US participants.