The main objective of this study is the comparison of Body Mass Index distribution among preschool children between 1997 and 2004. Using cluster and simple sampling chose 20 villages and 20 persons completed the questionnaires and measured their weight and height. The sample size was 3154 (stage 1 = 1585 cases and stage 2 = 1569 cases). Data of two stages was added to the file and was analyzed by spss.win soft-war. NCHS standard was used for comparison. The BMI percentiles by NCHS standard were used to classify subjects as follows: under weight, < 5th BMI percentiles; healthy weight, 5th-84th BMI percentiles; overweight, 85th-94th BMI percentiles; or obese, 95th = BMI percentiles. Gorgan a capital city and located in north of Iran and south east of Caspian Sea. In spite of boy’s weight increased about 0.1 kg, but height increased about 3.4 cm in second stage and t-test is significant between two stage by height (p< 0.001). Girl’s weight didn’t have any change, but height increased about 2.7 cm. t-test is significant between two stages by height (p< 0.001). The prevalence of obesity and overweight declined 17.36 and 4.7% respectively after 7 years. There is a statistical significant between two stages by obesity index (p< 0.05). The most outstanding results of this study is unvarying of weight and dramatically improving of height. The prevalence of obesity and overweight significantly declined after 7 years. Some health strategy that carried out by health managers in this area can caused this situation. Other studies are necessary for following the physical growth pattern in future.