Long-term morbidity and survival after orthotopic liver transplantation (OLT) are to a large degree determined by cardiovascular disease and cancer. Tobacco use is a well-known risk factor for both. The aim of this study was to examine smoking behavior before and after OLT and to define groups at risk for resuming tobacco use after OLT. In addition, we looked for a relation between smoking and morbidity after OLT. All 401 adult patients with a follow-up of at least 2 years after OLT were included. Data were collected from the charts. A questionnaire about smoking habits at 4 time points before and after OLT was sent to all 326 patients alive, and 301 (92%) patients responded. Both before and after OLT, 53% of patients never used tobacco, and around 17% were active smokers. Of the active smokers during the evaluation for OLT, almost one-third succeeded in cessation, often during the waiting time for OLT. Twelve percent of former smokers restarted smoking, mainly after OLT. Tobacco use was the highest in patients with alcoholic liver disease (52% were active smokers before OLT, and 44% were after OLT) and the lowest in patients with primary sclerosing cholangitis (1.4% were active smokers before OLT). At 10 years, the cumulative rate of malignancies was 12.7% in active smokers versus 2.1% in nonsmokers (P = 0.019). No effect on skin cancer or cardiovascular disease was found. In conclusion, smoking is a serious problem after OLT and increases the risk for malignancy. Prevention programs should focus not only on active smokers but also on former smokers. Liver Transpl 15: 648–655, 2009. © 2009 AASLD.