The purposes of this research are to investigate 1) personal factors contributing to the longevity of elderly 2) the dietary behavior of long-living elderly and 3) the relationship between personal factors such as:gender age BMI and dietary behavior. The samples are 29 of long-living elderly with ages more than 80 years old living in Tambon Tha Phi Liang Muang district Suphanburi province. The long-living elderly must be able to answer the questions. The statistics used to analyze data in this research are frequency percentage and Chi-Square (χ2). The data were analyzed using statistical tools. As for thier dietary behavior it was found that most long-living elderly usually have five food groups:eggs UHT milk paddy morning glory cabbage watermelon papaya and vegetable oils. They purchased these five groups of food for consumption. Boiling was the main method of cooking. They usually stored food in the refrigerator to keep them fresh. The relationship between personal factors and dietary behavior could be classified into 5 areas : types of food frequency of consumption sources of food methods of cooking and methods of food preservation. The finding found that gender age and BMI were related with food consumption. However cooking (boiling) was not related with statistically significant level at .05.