A review of the literature leads to the conclusion that there are no reliable figures on the impact of gambling advertising on the extent of problem gambling. To measure that impact appears as a very difficult research task. However, we can infer that gambling advertising does add to problem gambling, but with a smaller impact than other influential factors. Thus, alarming claims that gambling advertising substantially increases problem gambling and reassuring statements from gambling companies that advertising merely affects market share and has no impact on the prevalence of problem gambling both appear to be erroneous. Gambling providers are advised to avoid publishing advertising that elaborates on features of gambling known to relate to problem gambling. The controversial nature of gambling advertising is illustrated by the case of Sweden, where advertising and its impact on problem gambling have been hotly debated over the past decade.