Objective: To verify the prevalence of delay in gross motor development in cystic fibrosis (CF) patients. Study design: This is a cross-sectional observational study. A total of 15 children with CF were included in the analyses. The selection criteria was age between 6 and 42 months. Data on demographic, anthropometric, clinical characteristics and severity score (Shwachman) were obtained from patient records. The Bayley Scales of Infant and Toddler Development® - III Edition (BSITD-III) was used to assess motor abilities. Results: Motor development delay was observed in 26.7% (n= 4) of the children and, in 75% of these, there were statistically significant differences between gross and fine motor scores. Low stature, low weight and periods longer than 60 days at hospital showed statistically significant association with motor delay (p= 0.025, 0.032, 0.003, respectively). Conclusion: The prevalence of motor delay in the studied sample was high, suggesting that biological and ambient conditions of risk present in CF contribute to early motor deficits. Thus, the observation of the motor development in these patients is important for planning an adequate intervention.