Studies of Internet gambling have consistently shown that online gamblers are more likely to report disordered gambling behaviour than offline gamblers. However, little research has focused on whether this is a causal relationship or whether this risk factor is capturing a relationship with one or more missing variables. To address whether there is a strong causal argument for the effect of online gambling participation on problem gambling severity, we use a secondary data method that corrects for potential omitted variable bias. Once this issue is addressed, we find that past-year participation in online gambling is related to a decrease in problem gambling severity, which is the opposite of the popular view in current literature. The estimates in this study are found to be robust to various forms of online gambling, control variables and problem gambling measurement instruments. The findings were also consistent when using a representative sample from the United Kingdom and when using an online research panel from Ontario, Canada. As a primary force against the widespread adoption of Internet gambling has been public health concern over problem gambling, this study provides evidence that such decisions should be more closely considered by policymakers.