Evidence suggests that until 8 years of age most children are cognitively incapable of appreciating the commercial purpose of television advertising and are particularly vulnerable to its persuasive techniques. After this age most children begin to describe the selling intent of advertising and it is widely assumed this equips them with sufficient cognitive defences to protect against advertisers persuasion attempts. However, much of the previous literature has been criticised for failing to differentiate between childrena s awareness of selling versus persuasive intent, the latter representing a more sophisticated understanding and superior cognitive defence. Unfortunately there is little literature to suggest at what age awareness of persuasive intent emerges; our aim was to address this important issue. Children (n = 594) were recruited from each grade from Pre-primary (4 - 5 years) to Grade 7 (11 - 12 years) from ten primary schools in Perth, Western Australia and exposed to a McDonalda s television advertisement. Understanding the purpose of television advertising was assessed both nonverbally (picture indication) and verbally (small discussion groups of 3 - 4), with particular distinction made between selling versus persuasive intent. Consistent with previous literature, a majority of children described the selling intent of television advertising by 7 - 8 years both nonverbally and verbally, increasing to 90 by 11 - 12 years. Awareness of persuasive intent emerged slowly as a function of age but even by our oldest age-group was only 40 . Vulnerability to television advertising may persist until children are far older than previously thought. These findings have important implications regarding the debate surrounding regulation of junk food (and other) advertising aimed at children.