en Original Article Original Article - <strong>Background:</strong> Infertility is defined as one year unprotected intercourse without pregnancy. It greatly affects couples&#39; quality of life and has great impact on their careers everyday activities sexual and non-sexual relationships.<br> <strong>Objective:</strong> To study the prevalence of both primary and secondary infertility and demographic characteristics of it in Yazd province.<br> <strong>Materials and Methods:</strong> We studied 5200 married defined couples in 260 randomized clusters. These couples were interviewed based on using a structured questionnaire. Then for etiological evaluation infertile couples were referred to the Research and Clinical Center for Infertility.<br> <strong>Results:</strong> Among these couples 277 cases of infertility were encountered and the overall prevalence of infertility was 5.52% (95% CI from 4.9% to 6.1%). In total 170 couples (3.48%) had primary and 107 (2.04%) had secondary infertility. The prevalence of infertility in rural and urban areas was 5.3% and 6.8% respectively. Female factors were more common (57.5%) in etiologic assessment of infertility.<br> <strong>Conclusion:</strong> Our data showed a lower total prevalence of infertility in our people compared to the other countries. Furthermore there was significant difference in infertility prevalence between geographic parts of the province. Female factors and among them ovarian disorders were the main cause of infertility in central part of Iran. Epidemiology, Etiology, Infertility, Yazd. 117 122 http://ijrm.ir/browse.php?a_code=A-10-549-221&slc_lang=en&sid=1 Abbas Aflatoonian aflatoonian@yazdivf.org Yes Research and Clinical Center for Infertility, Shahid Sadoghi University of Medical Scienses, Yazd, Iran Seyed Mohammad Seyedhassani No Research and Clinical Center for Infertility, Shahid Sadoghi University of Medical Scienses, Yazd, Iran Nasim Tabibnejad No Research and Clinical Center for Infertility, Shahid Sadoghi University of Medical Scienses, Yazd, Iran