Using records of Internet gambling subscribers (n = 1,384), this study tested the Pareto principle: about 20% of customers, "the vital few," are responsible for about 80% of the activity, while 80%, "the trivial many," are responsible for the remaining 20%. Participants completed the Brief Biosocial Gambling Screen (BBGS) and had a history of betting on sports and/or online casino games during the twelve months before completing the screen. Using various measures, the vital few Internet gamblers ranged between 4.6% and 17.8% of the subscribers - smaller than the Pareto principle would suggest. Between 38% and 67% of the vital few and between 24% and 35% of the trivial many screened positive for gambling-related problems. This research suggests that the concepts of the "vital few" and the "trivial many" apply to Internet gambling.