Mail surveys are a very popular instrument for researchers as well as government agencies and commercial firms to obtain information about farmers. A large percentage of farmers do not respond to these mail surveys. To gain insight into why farmers do not respond and their preferences regarding mail surveys, farmers who did not respond to a mail survey were interviewed. From our field study it appears that a large proportion does not even read the questionnaire. Furthermore, the period in which the survey is sent along with the form and amount of compensation, the sender of the questionnaire, and the length of the questionnaire has a crucial impact on the willingness to participate.