Background. Epidemiological research has identifi ed a relationship between maternal physical activity, early nutrition and infant birth weight with likelihood of developing future diseases. The aim of the study was to determine a relationship between gestational weight gain and physical activity during pregnancy to the nutritional status of newborns.Material and methods. The presented study was conducted in the period from February 2010 until November 2012 in the gynecological and obstetric clinics in Warmińsko-Mazurskie voivodeship with various levels of reference. The research subjects included 510 women in the puerperal period aged 18-36. The scope of the research included an assessment of the selected anthropometric parameters of both pregnant women (body mass, height, BMI, gestational weight gain) and newborns (infant birth weight, infant length, Ponderal Index), as well as an analysis of the connections between the gestational weight gain, physical activity during pregnancy and anthropometric parameters of newborns.Results and conclusions. In the study group there was a signifi cant percentage of women characterised by an inactive lifestyle and excessive gestational weight gain. There were signifi cantly higher neonatal birth anthropometric parameters in women with abnormal excessive gestational weight gain than in women with normal and inappropriate – low gestational weight gain. The highest percentage of women with appropriate weight gain was observed in the group of women who are physically active, although this requires confi rmation in larger population. Our studies have not shown statistically signifi cant differences between the gestational weight gain and nutritional status of newborns in relation to the level of physical activity of pregnant women.