SummaryThirty‐two infants with Down's syndrome, who were enrolled in an early intervention programme were followed during the first 2 years of life. Progress in five developmental domains was monitored prospectively by evaluating the children at 6, 12, 18 and 24 months. The largest degree of retardation was consistently exhibited in the hearing and speech subscale. The locomotor subscale experienced the most severe decline over the 24 months and was the second most retarded domain at 2 years of age. The remaining three subscales, personal‐social, hand‐eye and performance, demonstrated less severe declines over time as well as actual increases in developmental quotients at specified points in time. The overall performance of female infants at 18 months was significantly better than that of male infants (P = 0·05). The degree of retardation of Down's syndrome infants receiving early intervention services differs according to chronological age, developmental domain a