Background: The main aim was to analyse the structure and body composition in untrained women after 12-week Nordic walking training. Material and methods: 26 women were divided into two groups: an EG-experimental group (n = 13) and a CG-control group (n = 13). The EG took part in 12-week Nordic walking training. All participants were examined twice: at the beginning and after the experiment. Body mass, waist and hips circumference; analysis of body composition (BIA method): BMI, body cell mass (BCM), total body (TBW), extracellular (ECW) and intracellular water (ICW); fat (FM), free fat (FFM) and muscle (MM) mass were recorded. The heart rate and lactate concentration were recorded to assess the exercise intensity. Results: The body composition analysis revealed significant changes: a decrease in ECW and an increase in ICW in the EG group. Insignificant changes were noticed: a decrease in ECW and FM, and an increase in TBW and ICW, FFM, MM and BMR were recorded in the CG. Conclusions: 12-week Nordic walking training affected the adipose tissue deposition, which prevented fat accumulation in lower body part. The used training was recognised to be a good way to maintain the basal body composition. An increase in ICW and a decrease in ECW at the same time were beneficial for intracellular mechanisms efficiency and prevented swellings.