Objectives: to evaluate the gross motor performance in infants aged six to 18 months old, through the Alberta Infant Motor Scale (AIMS), and to verify if there is an association between the nutritional status and the gross motor performance. METHODS: a cross-sectional case-control study which assessed the gross motor development of infants between six and 18 months old through the AIMS was conducted. Infants were divided into two study groups, the malnoutrished infants and the control group. Each group had 13 infants each, with 6 female participants and 7 male participants, equivalent in age, gender and socioeconomic status. The average age was 14,54 months old. The Mann-Whitney test (continuous variables) and the Exact Fisher Test (categorical variable) was used to compare both groups with a significance level of á=0.05. RESULTS: considering the Raw score and the AIMS' centile index (p= 0,023 e p= 0,002, respectively) a statistically significant difference was found between the groups, observing poor performance (below the 5th centile of the AIMS' normative curve) in 10 (83,3%) infants from the study group and in 2 (16,7%) infants from the control group. CONCLUSION: the results indicate that malnutrition is negatively associated with gross motor development of infants aged 6 to 18 months old. This reaffirms the importance of an integrated approach to help malnourished infants, including the monitoring of motor development and, if necessary, implementation of measures to improve this condition.