Objectives: The purpose of this study was to analyze the factors affecting weight loss effect of Gamitaeumjowee-tang and to see if weight loss could be predicted using influence factors and weight loss progress.\nMethods: From September 2016 to March 2017, we retrospectively reviewed the medical records of 139 patients who were visited to the Korean Oriental Clinic for 3 months. We conducted a regression analysis to determine whether age, gender, initial weight, patient health questionnaire-9, heart rate variability (HRV), sleep quality, drinking habit and the medication history of weight loss affect weight loss. We found weight loss prediction equations using multiple regression analysis applying significant factors and weight loss progress.\nResults: Gender and initial weight had a significant effect on weight loss in all periods (P＜0.001). HRV had a significant effect on primary weight loss (P＜0.01). Other factors did not have any significant effect on weight loss. Using the significant factors, weight loss of each period could be predicted from 23.9% to 44.6%, and tertiary weight loss could be predicted with 76.6% using factors, primary weight loss and secondary weight loss (P＜0.001).\nConclusions: This study suggests that weight loss effect of Gamitaeumjowee-tang maybe be affected by influence factors and that weight loss prediction equations using them can be used for obesity treatment.