Background: Providing care for an old person with a psychiatric disorder is a long-term and stressful process exerting negative outcomes on the caregivers' physical, psychological, and social health. Objectives: The aim of the study was to determine the burden among family caregivers of psychiatric elderly and its related factors. Methods: This descriptive study was conducted on 200 elderly psychiatric patients via convenient sampling, referring to the zare teaching psychiatric hospital of Sari, Iran. The sampling lasted from June to mid-November, 2015. Two questionnaires of demographics (the elderly and caregivers) and Zarit Burden Interview were used to collect the data. The data was analyzed using descriptive and inferential statistics, such as independent t-test, Analysis of Variance (ANOVA) and Scheffe Post Hoc test.