To date, there has been relatively little research on Internet gambling. Furthermore, there have been few studies comparing the behaviour of Internet gamblers versus non-Internet gamblers. Using the game of roulette, this study experimentally examined (a) the differences in gambling behaviour between online and offline gamblers, and (b) the role social facilitation in gambling behaviour between online and offline gamblers. A total of 38 participants played online and offline roulette either alone or alongside another gambling participant, and the players' chip placement and amount bet was recorded. The study found that those who gambled in online roulette placed more chips per bet and made riskier bets than those who gambled on roulette offline. The study also found that those who gambled alongside another gambler placed more chips and made riskier bets than those who gambled alone. Those who gambled online and in the presence of others, placed the highest number of chips per bet and made the riskiest bets.