The aim of this study was to examine the role of free-play modes on gambling behaviour in computer-based roulette. Eighty participants were randomly allocated to one of four pre-exposure conditions: no exposure (control group), a loss condition, a break-even and a profit condition in which the return to player was greater than 100%. Behavioural persistence and betting behaviour was subsequently monitored in a period of regular roulette play. The results showed that players given opportunities for free-play sessions bet significantly more per spin and wagered more credits in total than the control group, although no significant group differences in behavioural persistence were observed. The results suggest that the role of free-play modes, as they commonly appear on some Internet gaming sites, may need to be investigated further because of their potential role in altering player perceptions of the activity and their influence on risk-taking behaviour.