Sitting is required for the development of other motor actions. A normal time course in the acquisition of sitting is essential, any delay passing along the other developmental milestones. Therefore, our aim was to identify variables whose measures at the very beginning of sitting would allow estimation of sitting. Center of pressure (COP) data were collected from twenty-six typical babies with a beginning ability to sit upright. Spatial, temporal and frequency variables of sway were obtained in both medial/lateral (ML) and anterior/posterior (AP) directions. A discriminant function analysis (DFA) was conducted on these variables, plus age and gender, to identify potential predictors regarding the duration between onset and fully independent sitting. DFA is a technique able to predict outcomes from measures taken a priori, determining which variables differentiate between two or more naturally occurring groups. Three groups were identified based on time between onset and fully independent sitting (F = 65.337; p<0.001). Mean time for each group was 55.5, 83.44 and 96.56 days accordingly. Gender (p=0.025), Median Frequency (p=0.006), and Correlation Dimension (p=0.002) in ML direction were identified by DFA to be grouping predictive with 73.1% correct classification, with only two of the cases expected to achieve sitting earlier than actually occurred. A "leave one out" analysis retains 65.4% correctness with 4 cases of detrimental classification. In conclusion, the time course of sitting development can be predicted from measures taken at the earliest signs of sitting emergence. Subsequently, early identification of infants with developmental delays would benefit from early intervention.