Determinants of the decision to gamble not only include the gambler's biological and psychological constitution but also the structural characteristics of the gambling activity itself. Such characteristics may be responsible for reinforcement, may satisfy gambler's needs, and facilitate excessive gambling. Showing the existence of such relationships has great practical importance. Not only could potentially dangerous forms of gambling be identified but effective and selective legislation could be formulated. This paper outlines a history of the importance of structural characteristics in fruit machine gambling and then discusses the role of a number of distinct characteristics including pay out interval, multiplier potential, better involvement, skill, win probability, pay out ratio, suspension of judgement, symbol ratio proportions, the near miss, light, colour, and sound effects and naming. These are all examined in relation to the gambler's behaviour and/or cognitions. It is shown that structural characteristics of fruit machines have the potential to induce excessive gambling regardless of individuals' biological and psychological constitution and that such insights may help in decreasing fruit machine gambling's addictiveness potential and help in formulating effective gambling policy.