The purposes of this study were to evaluate the accuracy of glaucoma screening tests and to assess the prevalence of glaucoma in an elderly Thai population over 60 years of age. This was a cross-sectional study. 3706 subjects were recruited from 33 communities in the vicinity of Siriraj Hospital. All received an eye examination from ophthalmologists and general practitioners including visual acuity, Schiotz tonometry and optic disc evaluation in their residential communities. Subjects who were suspected of having glaucoma were re-examined at the Glaucoma Clinic, Siriraj Hospital. They were then classified as having definite glaucoma of a specific type or as not having glaucoma. The overall prevalence of glaucoma was 6.1 per cent (128/2092). The percentages of primary open angle glaucoma, primary angle closure glaucoma, normotension glaucoma and secondary glaucoma were 47.7 per cent, 41.4 per cent, 9.4 per cent, and 1.6 per cent respectively. The sensitivity and specificity of the screening tests performed by ophthalmologists were 100 per cent and 97.2 per cent and those performed by general practitioners were 21.7 per cent and 96.5 per cent.