The purpose of this study was to determine the status of nasal airway and olfaction of adult subjects born with choanal atresia (CA).A case-control study was conducted to compare the quality of nasal airway and olfaction in a group of adults born with CA to a similar group of normal subjects. Objective evaluation of nasal airway and olfaction were done respectively by acoustic rhinometry and the University of Pennsylvania Smell Identification Test (UPSIT).Thirty-six choanal atresia patients aged 16 to 36 were found in the medical records. Five bilateral and two unilateral cases were recruited for the study. An average score of 27/40 (moderate hyposmia) was obtained by the bilateral cases compared with 37/40 (normal) by the controls. These results were statistically significant (Wilcoxon signed rank test and sign test statistic, P = 0.03).Using the UPSIT, the bilateral CA patients have shown, on average, a moderate loss of the sense of smell when compared with normal controls of a similar age group. Acoustic rhinometry is not a useful study for posterior nasal conditions.