Assessing the relationship between thoracoabdominal mobility (TAM) in newborns (NBs) is relevant for a greater understanding of pulmonary kinematics. This study aimed to assess the association between TAM, hours of life and respiratory rate (RR) in term NBs. Healthy NBs were included in the sample. They were filmed for 2 min, with markers in the lateral region of the trunk, delimiting the thoracic and abdominal areas. TAM and RR were assessed using a MATLAB (R) routine. For kinematic analysis, an algorithm created graphs presenting thoracoabdominal mobility. A total of 26 NBs were evaluated. TAM was the only variable that exhibited a statistically significant intergroup difference, showing that the fewer the hours of life, the greater the mobility. Simple linear regression analysis showed that RR can explain 31% of the variation in abdominal mobility (p = 0.002). Thus, the fewer the hours of life, the greater the TAM of NBs, with a predominance of abdominal compartment mobility.