Background <p>Smoking addiction is the most important reversible risk factor affecting many organs, including the heart, lungs, and central nervous system. Smoking cessation alone should not be the sole focus of smoking addiction, and comorbidities should be considered.</p> Aims <p>In our study, the relationship between successful smoking cessation and vitamin D levels was analyzed.</p> Methods <p>This was a retrospective cohort study. Our study included patients who visited the smoking cessation outpatient clinic. All patients were started on the same dosage of cytisine active ingredient at the same time. After one month of treatment, smoking cessation success and vitamin D levels were compared. In addition, demographic data, the amount and duration of smoking, and smoking cessation success after treatment were recorded.</p> Results <p>Our study included 327 patients and the smoking cessation rate after treatment was 58.7%. A statistically significant correlation was found between vitamin D level and smoking cessation success. We found that patients with higher vitamin D levels had a higher smoking cessation success rate</p> Conclusion <p>Many studies have reported a relationship between addiction and vitamin D level. Vitamin D supplementation has been used in many addiction treatments, and positive results have been obtained with this treatment. In our study, we found that patients with low vitamin D levels had low smoking cessation success rates. In our study, we found a relationship between high vitamin D levels and smoking cessation success and suggested that vitamin D supplementation should be initiated in patients with low vitamin D levels to increase the smoking cessation rate.</p>