The pandemic of the Covid-19 virus caused major changes in people's daily lives, and the whole situation had the greatest impact on preschool children and caused significant changes in their daily routines. This paper explains in more detail the morphological (anthropometric) characteristics and their dimensions. Special emphasis is placed on the importance of conducting anthropometric measurements, the positive effects of proper nutrition and physical activity in preschool age. There's an ever-greater incidence of obesity as a contemporary problem that an increasing number of children and adults have to face, and the number of overweight people is drastically increasing. In order to determine the impact of the Covid-19 virus pandemic on the morphological characteristics of children, the research has been conducted in a kindergarten in two preschool groups. The aim of this research was to determine whether there is a statistically significant difference in the body mass index between the measurements taken before and after the pandemic period and the prevalence of overweight and obesity in a sample of preschool children. The first study was conducted before the period of the Covid-19 pandemic on a sample of a total of 38 children, and the second study was conducted after the period of the pandemic on a sample of a total of 39 children. The results of anthropometric measurements of body mass and body height, from which the body-mass index was calculated were used to determine the morphological characteristics and nutritional grade of the children involved. The statistical processing of the data showed the basic descriptive parameters and the t-test was used to determine the differences between the measurements before and after the pandemic. The results of the conducted research showed that there are no statistically significant differences in the results of the body mass index between the measurements carried out before and after the period of the Covid-19 virus pandemic on a sample of preschool children. Also, changes in the results by nutritional categories confirmed that after the Covid-19 virus pandemic, the prevalence of obesity in a sample of preschool children increased, while the prevalence of overweight decreased.