Introduction and purpose: Researchers pay more attention toward mental health status of elderly due to increased life expectancy and aged population.  Therefore, this study aimed to identify prevalence of mental disorders and its related factors among elderly at the Birjand city.

Materials & Methods: This cross sectional study was conducted among 389 elderly at Birjand city using multistage sampling method. Data were collected using Goldberg's General Health Questionnaire-28 (GHQ-28). We used SPSS version 18 to analyze data using t-test, ANOVA and Pearson correlation coefficient.

Findings: Participants in the present study aged 63.65±3.74 years old in average. Slightly more than half (51.2%) of elderly was suspected to mental disorders, 3.3% had depressions, 14.1% had anxiety, 15.2% had physical dysfunction and 14.1% had Social dysfunction. Prevalence of mental disorders among older age, female, low education, unemployed and disabled elderly was significantly (p=0.001) higher than their counterparts.

Conclusion: Our findings indicated high prevalence of mental disorders among elderly. Therefore, it is recommended to utilize screening tools for early diagnosis of mental disorders especially among women, low education, unemployed and disabled elderly.