Chasing refers to the escalation of betting behaviour. It is conventionally seen when losing (loss chasing) but can also be seen after wins. Diagnostic and screening items for gambling problems describe chasing as returning ‘another day’ to gamble, i.e. between-session chasing. However, gamblers may also chase outcomes within sessions, and this may be particularly relevant in the online gambling environment. The current study focused on two expressions of within-session chasing: i) increasing the bet amount, or ii) a reduced probability of quitting the session, as a function of prior losses or wins. These expressions were examined across five categories of online gambling products: slot machines, probability games, blackjack, video poker, and roulette. For losses, gamblers tended to bet more, and played longer sessions, after immediate losses, but they reduced their bet and played shorter sessions when losing cumulatively. The reversed patterns in the cumulative model may be due to financial constraints on the gambler. For wins, gamblers played shorter sessions as a function of both immediate and cumulative wins, but they also increased the bet amount when winning. Chasing patterns were fairly similar across the different product categories, and we saw limited evidence for our hypothesis that chasing is greatest for online slot machines as an established high-risk category. Overall, chasing was seen to be a multi-faceted construct, varying across these two behavioural expressions, by the immediate or cumulative timeframe of prior outcomes, and by game type.