Purpose To investigate the prevalence of the Q368STOP myocilin mutation in a population-based cohort: the Blue Mountains Eye Study (BMES). Design Population-based study. Methods DNA was extracted from 2,142 individuals collected through the BMES, including 31 individuals with glaucoma. All individuals were screened for the presence of the Q368STOP mutation of myocilin. Genotyping of the microsatellite markers My5, My3, D1S2815, and D1S1619 was also undertaken. Results None of the 31 open-angle glaucoma-positive individuals presented with the Q368STOP mutation. However, two individuals (aged 56 and 72) with no clinical signs of OAG, were identified with this mutation. Allele sharing at the four microsatellite markers defining the Q368STOP disease haplotype for OAG was found in these two individuals. Conclusions The Q368STOP myocilin mutation occurs at a low prevalence (0.09%) in a general, older population.