A developmental questionnaire, encompassing the ages from 4 wk-36 mo. was devised that, when completed by parents, can be used to screen children as being developmentally normal, questionable or abnormal. A total of 526 infants were screened by this questionnaire at 28 wk of age and then examined at 40 wk of age by a full Gesell Developmental and Neurologic Examination. Underscreening of those with major abnormalities was 2.6%, and of those with minor abnormalities, 10%. Overscreening was 6%. In view of the high reliability and validity of the full Gesell Developmental and Neurologic Examination on which the questionnaire is based, the relatively small percentages of overscreening and underscreening make it the most accurate and useful screening questionnaire to date.