This study addresses the impact of prohibition of note acceptors on gambling behaviour and gambling problems among Norwegian adolescents. Data comprised school surveys at three time points; 2004 and 2005 (before intervention) and 2006 (after intervention). Net samples comprised 20.000 students aged 13-19 years at each data collection. Identical measures of gambling behaviour (gambling frequency and expenditures on slot machines) and indicators of problem gambling (SOGS-RA and Lie/Bet) were assessed at all three time points. No significant changes in gambling behaviour and problem gambling were observed in the period prior to the intervention, whereas slot machine gambling frequency was reduced by 20%, the proportion that gambled frequently on slot machines was reduced by 26%; overall gambling frequency was reduced by 10% and the proportion of problem gamblers (SOGS-RA 4+) was reduced by 20% after the intervention when controlling for potential confounders. It is suggested that these findings can be attributed to the removal of the note acceptors on slot machines.