We explored the performance of the Fagerström Test for Nicotine Dependence (FTND) in a sample of 1378 daily smokers and 1058 ex-smokers who participated in a survey study of the Netherlands Twin Register. FTND scores were higher for smokers than for ex-smokers. Nicotine dependence level was not associated with age. FTND score was highly correlated with the maximum number of cigarettes smoked (even after excluding the item 'number of cigarettes per day' from FTND), but the FTND score showed a low correlation with age of first cigarette and total number of years smoked. In a subsample of smokers (n=143) and ex-smokers (n=181) the test-retest correlations for the FTND were high. In general, the performance of the FTND in ex-smokers was comparable with that in smokers. These findings suggest the FTND to be a valuable tool for studies of nicotine dependence in large epidemiological samples. © 2004 Elsevier Ltd. All rights reserved.