Because there has been no suitable diagnostic instrument for evaluation of olfaction in children, we designed an odorant identification test for that purpose. We screened 40 microencapsulated odorants ("scratch 'n' sniff" cards) by randomly grouping them into 40 overlapping sets of five odorants each. Forty-one children, 4 and 5 years of age, tried to identify each test odorant, selecting their responses from among five photographs depicting the substances in the set of odorants. We used the results to select a subset of five odorants (baby powder, bubble gum, candy cane, fish, and orange). To determine how well these odorants could be identified by normal children, we tested another 134 subjects, 3 1/2 to 13 years of age. For children 3 1/2 years to 5 years 4 months of age, the mean (+/- SEM) percentage of correct responses increased from 66% +/- 8% to 92% +/- 2%. Thereafter the mean percentage of correct responses remained at a plateau of about 90%. The 10th percentile for the percentage of correct responses tended to be higher for girls than for boys throughout childhood. We concluded that this set of five odorants can be correctly identified by most normal children 5 years of age or older. The performances of three older subjects with Kallmann syndrome were all subnormal, but the overall efficacy of the test for evaluating children with olfactory deficits needs to be determined.