Objective: To assess the prevalence of pseudoexfoliation syndrome (PEX) and its associations in a population-based setting. Design: Population-based, cross-sectional cohort study. Participants: Of 4403 eligible subjects with an age of >= 50 years, 3468 individuals (78.8%) participated in the Beijing Eye Study 2011 (mean age, 64.6 +/- 9.8 years; range, 50-93 years). Methods: All study participants underwent a detailed ophthalmologic examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit-lamp-based biomicroscopy. Main Outcome Measures: Prevalence and associations of PEX. Results: Slit-lamp examination results were available for 3022 study participants (87.1%). Definite pseudoexfoliation was observed in 72 of the 3022 subjects, with a prevalence of 2.38% (95% confidence interval [CI], 1.84-2.93). Suspected PEX was detected in 104 of the subjects (3.44%; 95% CI, 2.8-4.1). The overall prevalence of PEX (definite and suspected) was 176 of 3022 or 5.82% (95% CI, 4.99-6.66). In 80 subjects (45.5%), PEX was detected in both eyes, whereas it was detected only in the right eye in 42 subjects (23.9%) and only in the left eye in 54 (30.7%). The prevalence of PEX increased from 1.1% in among those 50 to 54 years old, to 3.5%, 5.7%, and 11.8% among those 60 to 64 years, 70 to 74 years, and >= 80 years, respectively. In multivariate analysis, presence of PEX was significantly associated with older age (P<0.001; odds ratio [OR], 1.08; 95% CI, 1.04-1.10), shorter axial length (P = 0.03; OR, 0.82; 95% CI, 0.68,0.98), and shallower anterior chamber (P = 0.03; OR, 0.59; 95% CI, 0.36-0.95). We found that PEX was not associated (all P>0.05) with sex, diabetes mellitus, blood pressure, psychological depression, smoking, dyslipidemia, body mass index, central corneal thickness, corneal diameter, optic nerve head measurements, choroidal thickness, retinal vessel diameters, early age-related macular degeneration, or retinal vein occlusion. Conclusions: In a North Chinese population aged >= 50 years, the prevalence of definite PEX was 2.38% (95% CI, 1.84-2.93), suspect PEX was 3.4% (95% CI, 2.8-4.1) and overall PEX was 5.82% (95% CI, 4.99-6.66). We found PEX to be associated with older age, shorter axial length, and shallower anterior chamber. The relationship between PEX and glaucomatous optic neuropathy remained inconclusive among our population. (c) 2013 by the American Academy of Ophthalmology.