Objective: To determine the changes in smoking habit among patients with oral squamous cell carcinoma (OSCC) diagnosed and treated in the Service of Stomatology (Valencia University General Hospital. Valencia, Spain). Material and methods: The study involved 123 patients with a history of OSCC interviewed by telephone on their smoking habits at the time of the diagnosis and modifications in habits subsequently. The mean age at diagnosis was 60 years and 9 months (standard deviation, SD ± 12 years and 2 months). Males predominated (61.8%) over females (38.2%). The mean time from the diagnosis of OSCC to the survey was 4 years and 6 months (SD ± 3 years and 6 months). Results: Almost one-half of the patients (45.5%) were active smokers at the time of the diagnosis, with a mean duration of the habit of 34.9 years (SD ± 12 years and 7 months). In turn, 19.5% of the patients were ex-smokers at diagnosis, with an average of 13 years and 9 months (SD ± 9 years and 4 months) from smoking cessation to the development of cancer. A total of 57.1% of the smokers abandoned the habit at diagnosis, 8.9% continued to smoke to the same extent as before, and 33.9% reduced smoking. Conclusion: A full 44.4 % of our patients diagnosed with OSCC continued to smoke despite warnings of the risks, and although the majority claimed to have reduced their smoking habit, interventional strategies would be indicated to help ensure complete smoking cessation.