This cross-sectional study analyzed age-related changes in normal and abnormal measurements of the head and face in three age categories in 115 Down's syndrome patients 1 to 36 years old. The frequency of normal measurements significantly surpassed that of abnormal ones in each category. Clinically, the key task was to ascertain differences between the youngest and oldest patients. In age group 1 (1 to 5 years), normal measurements in three of the six craniofacial regions were significantly more frequent than abnormal ones. In age group 2 (6 to 15 years) the percentage of normal measurements significantly increased, influenced by higher growth rates in the period of maturation, which coincided with this category. In age group 3 (16 to 36 years) the percentage of normal measurements significantly increased in the head and ear but decreased in the other regions, significantly in the orbits. The frequency of both optimal and severely abnormal measurements changed significantly from age group 1 to 3 in only five measurements each, with no consistency in the direction of results. Abnormal measurements qualified as stigmata and were recorded in 40% (10 of 25) in five regions: three in the face; two in each of the head, orbits, and ears; and one in the nose. Marked epicanthi covering the endocanthion decreased from 35.0% in age group 1 to 8.7% in group 3. In age group 1, the frequency of normal body height (20.7%) in both sexes was significantly less than subnormal (70.3%) but significantly decreased in age group 2. Mean height in group 3 was enough to rule out short stature as a stigmata of Down's syndrome. The study was limited by small numbers, particularly in the variations of normal and abnormal, but the trend toward normality after maturation suggests that reconstructive surgery should be delayed until this time.