Seltzer, C. C. (Harvard School of Public Health. Boston. Mass. 02115). R. Bosse and A. J. Garvey. Mail survey response by smoking status. Am J Epidemiol 100:453–457,1974.—A detailed smoking history questionnaire was mailed to a series of 1987 white male veterans participating in the Normative Aging Study of the Veterans' Administration Outpatient Clinic in Boston, Mass. Response time from mailing date to return date was determined and then compared by various smoker categories. Although a total response rate of 96% was achieved after six months, the results showed that cigarette smoker response rates were considerably lower than the other smoker categories within 30 days and within 60 days of the original mailing date. Cigarette smokers would therefore be under-represented if the data collection had ended within these spans of time; and even to some extent after six months had elapsed from time of original mailing. A relationship was also found between amounts of cigarettes smoked and rate of response with heavier smokers being slowest to respond. The implications of the findings with respect to cohort studies of smoking and health are discussed.