To maintain reduced body weight by behavioral therapy in moderately obese patients, body weight was measured four times daily and charted in a weekly graph. Seventytwo female patients with simple obesity were divided into two groups: 55 patients with appliance of charting of weight pattern (group-I), and 17 patients without the charting (group-II). The percentage of patients followed for 2 years was different between group-I (87%) and group-II (65%) during 2 years after completion of weight reduction therapy interviews (p<0.05). Fortyeight of group-I patients succeeded in decreasing their weight by 15.2 ± 1.5 (mean ± SEM) kg during the 6.5 ± 0.8 months of the therapy interviews. They were followed up for 3.8 years with no rebound weight gain. Eleven patients in group-II also succeeded in decreasing their weight by 16.8 ± 1.9 kg during 7.8 ±1.3 months but their body weight rebounded by 9.0 kg during the 2-year followup period. Twelve of 15 male patients with weight charting maintained reduced weight during 4.3 years. It was easier and more effective for obese patients to maintain weight graphs for the longer period than to record no weight graphs. Obese patients could themselves monitor irregular weight patterns produced by overeating and correct the irregularities in food intake and daily lifestyles. This seems to explain why the illustration of daily fluctuations of weight measurements was useful for long-term maintenance of weight reduction.