AIMS: The purpose of the present study was to examine differences between frequent, infrequent and non-gamblers in autonomic arousal, as indexed by heart rate, while playing a fruit machine and controlling for the confounding effect of movement. DESIGN: The experiment employed a between-subjects design, with a total of three groups being investigated—two experimental groups (frequent and infrequent gamblers) and a control group (non-gamblers). SETTING: To enhance ecological validity the study took place within an actual gambling setting, in Glasgow city centre. PARTICIPANTS: A total of 63 participants, 21 for each of the three groups, who were matched for age and gender, took part in the study. MEASUREMENTS: In terms of autonomic arousal, measurements were taken using a Pulse Oximeter (Pulsox-3I-Minolta Company Limited Milton Keynes, UK). In addition, a questionnaire was employed to measure levels of gambling severity (SOGS). FINDINGS: Frequent gamblers were found to have significantly higher levels of autonomic arousal than infrequent and non-gamblers, with the frequent gamblers arousal levels continuing to rise after play, unlike the other two groups. Interestingly, novel findings to arise from this research involved the fact that the specialist play characteristics of the fruit machine, such as bonuses, nudges and features, were found to be as arousing as wins. CONCLUSIONS: The main hypothesis was supported, suggesting that arousal is indeed a key factor in fruit machine gambling. The research has value, as few studies have examined specifically the differences between frequent, infrequent and non-gamblers, and no studies have investigated the arousal associated with the actual dynamics of fruit machine play (i.e. bonuses, nudges, features, wins). The arousal associated with modern British fruit machines suggests a high potential for addiction.