Many mail surveys have been conducted in Japan since the 1950's. Unfortunately, their response rates have been lower than other methods of administration. Various difficulties that result from the lack of an interviewer are major contributing factors of the lower response rates. This paper provides some guidelines regarding the design of mail questionnaires, the timing of the follow-ups, and other operational details. Mail surveys can potentially achieve high response rates. Further, their response rates in rural and urban areas are very similar. In addition, the response rates of mail surveys were found to be unrelated to the educational level of the respondents. A problem of mail surveys is the omission of questions by some respondents. However, there are usually few omitted questions and the overall quality of answers is usually better. The tendency to leave unanswered some branching questions is discussed and suggestions are provided how to decrease it.