Background: Recent several reports emphasized A1c variability along with average blood glucose determined by Alc. Many studies have been showing the relationship of A1c variability with chronic diabetic complications. But, associations between patterns or degrees of A1c variability and influential factors have not been studied much. Therefore, this study aimed to evaluate the relationships of A1c variability for 10 years and beta cell function at the time of diagnosis in type 2 diabetes in clinical practice.