The quality of life is a multidimensional notion. When studying it, one should take the physical, the psychological, the social, and the professional aspects into consid eration. Among them, the notion of the influence of obesity, understood as a modern -age disease, relates the quality of life to the notion of health, in the aspect of physical activity. The aim of the study carried out, was to determine the relationship be tween obesity in 18 -25 year - olds, and their physical activity, as well as the quality of their lives. The study was carried out by means a WHOQOL - BREF, and IPAQ survey questionnaires carried out on a group of 100 participants. The control group included pe ople whose BMI was within the norm, whereas the study group comprised people whose BMI was over 25. The results of the study have shown obesity to have a statistically significant negative impact on the quality of life in the physical, and mental domains, and as far as the general perception of health was concerned. In the study group, the mean weekly energy expenditure, was lower than in the control group. The physical activity of the obese, includes, mainly, activities based on light effort, and to a less er extent, those based on moderate effort. A comparative analysis has shown the level of physical activity to be significantly lower in obese women, in each type of physical effort, except light effort. This difference does not exist between the study, and control groups of men.