Study aim: the aim of this study was to assess the step counts of children and adolescents with different BMIs and to present the results in relation to the step count recommendation. Material and methods: the study included data from 175 girls, aged 12–18 (45 participants from primary school, 69 participants from junior high school and 61 participants from high school). Voluntary participants were recruited from public schools in Poland. Step counts were measured using pedometers (Yamax Digi-Walker SW 701) over seven consecutive days. Results: the recommended level of 12000 steps per day was achieved by only 14.9% of participants. The step counts performed by girls, especially at the primary school age, are currently insufficient. Participants’ achievement of the recommended step count level correlated with a lower BMI. Conclusions: few female children and adolescents are meeting daily step recommendations, which highlights the importance of school and community-based programmes designed to increase daily activity patterns.