Prepaid monetary incentives are used to address declining response rates in random-digit dial surveys. There is concern among researchers that some respondents will accept the prepayment but not complete the survey. There is little research to understand check cashing and survey completing behaviors among respondents who receive prepayment. Data from the International Tobacco Control Four-Country Study—a longitudinal survey of smokers in Canada, the United States, the United Kingdom, and Australia—were used to examine the impact of prepayment (in the form of checks, approximately US$10) on sample profile. Approximately 14 percent of respondents cashed their check, but did not complete the survey, while about 14 percent did not cash their checks, but completed the survey. Younger adults (Canada and United States), those of minority status (United States), and those who had been in the survey for only two waves or less (Canada and United States) were more likely to cash their checks and not complete the survey.