The literature is bereft of information about the age at which infants with Down syndrome (DS) acquire motor skills and the percentage of infants that do so by the age of 12 months. Therefore, it is necessary to identify the difference in age, in relation to typical infants, at which motor skills were acquired and the percentage of infants with DS that acquire them in the first year of life. Infants with DS (N = 20) and typical infants (N = 25), both aged between 3 and 12 months, were evaluated monthly using the AIMS. In the prone position, a difference of up to 3 months was found for the acquisition of the 3rd to 16th skill. There was a difference in the percentage of infants with DS who acquired the 10th to 21st skill (from 71% to 7%). In the supine position, a difference of up to one month was found from the 3rd to 7th skill; however, 100% were able to perform these skills. In the sitting position, a difference of 1-4 months was found from the 1st to 12th skill, ranging from 69% to 29% from the 9th to 12th. In the upright position, the difference was 2-3 months from the 3rd to 8th skill. Only 13% acquired the 8th skill and no other skill was acquired up to the age of 12 months. The more complex the skills the greater the difference in age between typical infants and those with DS and the lower the percentage of DS individuals who performed the skills in the prone, sitting and upright positions. None of the DS infants were able to stand without support. (Contains 4 tables and 1 figure.)