Objectives: To characterize and compare sociodemographic profiles, game-play patterns, and level of addictive behaviors among adults who gamble online and those who do not, and to examine if, at the population level, online gambling is associated with more risky behaviors than offline gambling. Methods: Respondents were 8,456 offline gamblers and 111 online gamblers who participated in a population-based survey conducted in the province of Quebec, in 2009. The study sample is representative of adult general population. Results: There is an unequal distribution of online gambling in the population. A disproportionate number of men, young people, and students say they participate in online gambling. Poker players are overrepresented among online gamblers and gambling behaviors tend to be more excessive on the Internet. Compared with offline gamblers, online gamblers report more co-occurring risky behaviors, namely alcohol and cannabis use. Conclusion: Those who gamble online appear to be more at risk for gambling-related problems, but the present findings alone cannot be used as evidence for that conclusion. Future research designs could combine longitudinal data collection and multilevel analyses to provide more insight into the causal mechanisms associated with online gambling.