Aim: The aim of this study to explain the interaction between the body mass index (BMI) and demographic features for patients with pilonidal sinus.

Materials and method: The patients who have pilonidal sinus were divided into two groups. 249 patients were included this retrospective study. Group I referred patients whose BMI were >25 (n=130) and Group II referred patients whose BMI <25 (n=119). All patients informations were recorded.

Results: Male gender were higher both groups, and it was statistically significant for Group I (p<0.05). Smoking cigarettes in group I were 77 (59.2%) patients and group II were 50 (42%) patients (p<0.05). University lecturers and civil servants were much more in group I wheras students were much more in Group II (p<0.05). Clinical outcomes were similar both groups. Six and more sinus orifice found in obese group (p<0.05).

Conclusion: Male gender were higher in obese group. Patients who spent their time sitting for a long time period in their jobs were found in both groups. But there was no differences clinical outcome for this patients. However sinus orificial number in obese group more than the other.