Body Mass Index [BMI] is a measures of adiposity of a person with respect to his or her body weight and height. The comparison of BMI between Gas flaring and Non-gas flaring communities in Southern Ijaw Local Government Area was the aim of this study. Weight and height were measures from 1000 adult volunteered subjects ( 550 male and 450 females) within the ages of 18-45 years from Five [5] gas flaring communities viz; Oporoma, Tebidaba, Ogboinbiri, Peremabiri, Koluama and Five [5] Non-Gas flaring communities such as Ekowe, Nangi-Ama, Anyama, Oweikorogha and Amassoma. Height was taken as the participant was asked to stand erect with barefoot and a measuring tape was placed from the heel to the head vertex. Weight was taken from the subject standing on the weighing balance. Body Mass Index [BMI] was calculated as; weight[kg] /height [m2].The results of the mean height of the Gas flaring communities is 5.60±0.03 for males and 5.24±0.01 for females. Weight is 69.15±0.94 and 64.86±1.38 for male and female and BMI of 24.61±0.83 for males and 26.0±0.97 for females. The mean height for males and females Non-gas flaring communities are 5.65±0.03 and 5.92±0.46, weight of 65.28±0.79 and 61.49±1.29 and with a BMI of 22.18±0.34 and 22.54±0.52 for males and females. 20% of the males and 23.8% of the females of Non-gas flaring Southern Ijaw people are overweight and obese. 30.2% of the males and 38.9% of the females of Gas flaring Southern Ijaw people are overweight and obese. The inhabitant of Southern Ijaw Local Government area are prone to stroke, cardiovascular diseases, high blood pressure, diabetes mellitus and other associated overweight and obese problems. They should exercise regularly, reduce high calories foods, frequent health and medical check-ups, Government and Multinational companies should stop gas flaring.