While premature infants are generally regarded as at high risk for developmental delay, and many early intervention programs are specifically targeted toward premature infants, there is a general consensus that: 1. full age adjustment is necessary (to compensate for prematurity), and 2. developmental delay cannot be detected accurately for several years due to extreme variability in delayed infants or their test results. In this study, 44 premature infants (mean gestational age 29.0 weeks, mean birthweight 1291 grams) were evaluated for suspected developmental delay at least twice, using the Bayley Scales of Infant Development Mental Development Index, in a high risk infant follow-up clinic. Mean age at initial testing was 12.8 months and at follow-up testing was 27.6 months. T-tests and linear regression were used to evaluate the effects of age adjustment at initial testing upon later developmental scores. Results obtained showed that: 1. 50% correction for prematurity produced the most consistent developmental test scores over time 2. both full correction and no correction produced scores that were significantly different than later developmental measures (mean difference from test 1 to test 2 +8.1 to -11.8, t values 2.40 and 2.10, p=0.02 and 0.04, respectively) 3. when 50% correction was used, developmental scores were remarkably consistent over time, and accurately predicted developmental delay. It is recommended that clinicians utilize 50% age adjustment when evaluating premature infant development.