Two studies conducted in Massachusetts and Nevada evaluated the efficacy of a self-help toolkit for problem gambling. Individuals concerned about gambling-related problems, in response to public notices and newspaper advertisements, volunteered for a randomized trial of the self-help toolkit, Your First Step to Change: Gambling. Participants were randomly assigned to 1 of 3 conditions: (a) a printed toolkit, (b) the toolkit and a brief guide to the toolkit's content, or (c) assignment to a wait-list condition. Participants, 145 in Massachusetts and 170 in Nevada, reported their gambling behavior, beliefs and attitudes about chance, and recent and planned help seeking at baseline, 88% at 1 month later, and 79% at 3 months later. Findings for the complete and intent-to-treat analyses at both sites indicated that participants significantly improved. At the end of the study period, significantly more toolkit recipients than control group participants reported recently abstaining from gambling. Minimally invasive, self-directed resources like this self-help toolkit can assist remediating gambling-related problems among gamblers who do not engage in formal treatment.