The current study evaluated the effectiveness of widely used self-help materials for quitting smoking. Five hundred and seventy smokers volunteered during a baseline survey to participate in the evaluation. After random assignment, 200 were mailed National Cancer Institute (NCI) "Quit for Good" materials, 200 the Minnesota "Quit and Win" program, and the remaining 170 were assigned to a nonintervention control condition. Results at 7-month follow-up failed to indicate treatment effects either for abstinence or for reported quit attempts. A number of smokers quit prior to the mailing of self-help materials, suggesting that a telephone prompt in itself may have been an important stimulus to cessation. Overall abstinence at follow-up was 10%. Contrary to expectation, successful participants were less likely to use a number of specific preparation strategies for quitting. The results are instructive in providing a large-scale assessment of self-help materials in a population of smokers that was not specifically seeking treatment.