Obesity is considered a global epidemic worldwide. During the COVID lockdown, many daily habits changed not only for adults, but also for children. These changes are likely to further increase the prevalence and severity of obesity, which could lead to early health problems and chronic diseases. Therefore, it is important to identify preventable and non-preventable risk factors of obesity, which would be useful in planning long-term obesity prevention programmes in the country. The aim of the study was to investigate the prenatal and postnatal obesity risk factors in obese and normal weight children and adolescents. The prospective study from 2013 to 2018 included 198 children and adolescents — 181 children with obesity and 17 children with normal body weight who attended a paediatric endocrinologist. No statistically significant differences in prenatal risk factors of obesity were found between normal weight and obese children in the study: birth weight (