The purpose was to study the therapeutic effects of 12 weeks of supervised exercise training at maximal fat oxidation intensity (FATmax) on body composition, lipid profile, cardiovascular function, and physical fitness in overweight or obese older women. Thirty women (64.2 ± 5.1 years old; BMI 27.1 ± 2.3 kg/m²; body fat 41.3 ± 4.6%) were randomly allocated into the Exercise or Control groups. Participants in the Exercise group were trained at their individualized FATmax intensity (aerobic training), three days/week for one hour/day for 12 weeks. The Exercise group had significantly decreased body mass, BMI, fat mass, visceral trunk fat, and diastolic blood pressure. Furthermore, there were significant increases in high-density lipoprotein-cholesterol, predicted VO₂max, left ventricular ejection fraction, and sit-and-reach performance. There were no changes in the measured variables of the Control group. These outcomes indicate that FATmax is an effective exercise intensity to improve body composition and functional capacity for older women with overweight or obesity.