Introduction: Obesity is a chronic disease and a public health problem that in some studies, is introduced as an important risk factor for catching sleep apnea. The present study has sought to investigate the relationship between obesity, body mass index and sleep apnea in patients with type II diabetes.

Methodology: This cross-sectional study was conducted in 1389 on 100 diabetic patients referred to the Diabetes Unit of saghez city using available easy sampling. Patients' height, weight, waist circumference and blood pressure were studied. Using the Berlin questionnaire, patients were divided into high and low risk for sleep apnea groups. Data were analyzed by SPSS software (Version 18) using descriptive statistics, independent t-test and Chi square and. P value was less than 0.05 and it was considered as statistically significant

Results: 46 diabetic patients (52.6% of males and 44.4% women) were at high risk for sleep apnea. There was a significant association between obesity and sleep apnea (p<0.002). After controlling the  variables,i.e., waist circumference and blood pressure, sleep apnea risk in obese patients was 4 times the other patients (95%CI:1.45-11.19, p<0.007). There was a significant association between sleep apnea and hypertension (p<0.002).

Conclusion: The body, mass index and sleep apnea in patients with type II diabetes are related.