Half of all children with disabilities are not identified before school entrance, which precludes their participation in early intervention programs. Such programs have known value in reducing high school drop-out rates, increasing employment, delaying child-bearing and reducing criminal behaviour. Although there are many screening tests that can greatly improve detection rates, these have not been popular in primary care due to test length, difficulty managing children's behaviour, etc. An alternative is to carefully elicit and interpret parents' concerns. Research shows that parents' concerns are as accurate as quality screening tests and that parents are equally able to raise important concerns regardless of differences in education and child-rearing experience. Parents' concerns can be elicited quickly and 92% of parents can answer questions in writing while in exam or waiting rooms. Unlike screening tests, use of parents' concerns facilitates an evidenced-based approach to comprehensive surveillance and aids in making a range of other important decisions about children's developmental and behavioural needs. These include when to: offer suggestions on developmental promotion; watch children more vigilantly; screen for emotional and behavioural problems; advise families about behaviour management; offer reassurance and routine monitoring of development that is likely normal; administer a second screening test; or refer for additional testing and the kinds of testing needed.