Background: Pterygium is a common ocular disease with etiology that has not yet well understood. Study on adult populations show the prevalence of pterygium tend to begin at fifth decade of age. The aim of this study is to determine the prevalence of pterygium and its relation to age, gender, educational level, occupation, hours spent outdoors per day, use of protective equipments, hypertension, and smoking as risk factors of pterygium among population age 50 years and above in Bali. Method: An analytic cross sectional study was conducted among population age 50 years and above in Bali between November to December 2015. The data were collected by interview using questionnaire and examinations. There were 720 subjects involved in this study. Chi square and multivariate analysis using Poisson regression were used for detecting association between risk factors with pterygium. Results: Pterygium was found in 36.4% subjects. Multivariate analysis showed pterygium was significantly related with educational level and occupation (APR 0.858; 95% CI 0.741-0.995 and APR 1.755; 95% CI 1.302-2.366, respectively). Conclusion: Prevalence of pterygium in population aged above 50 years in Bali was 36.4%. Pterygium was significantly associated with educational level and occupation in population aged above 50 years in Bali.