Objective To calculate couple-year of protection (CYP) by conversion coefficient (F) of tubectomy and vasectomy in urban and rural regions of Iran. Methods A total of 103 450 married women aged 10-49 years in 2005 across urban and rural regions of Iran were sampled by multi stage cluster sampling. The data were collected by household survey and direct interview and analyzed by STATA8.0 software and survey analysis commands. Results Mean age of the women at the time of tubectomy estimated 31.9 years and conversion coefficient of tubectomy was 17.1 ± 0.1. Mean age of women at the time of her husband vasectomy estimated 31.48 years and its conversion coefficient was 17.5 ± 0.1. Cluster analysis defined different regions of Iran on the basis of evaluated conversion coefficients of tubectomy and vasectomy which both of them presented seven clusters. Literacy of women and total coverage of family planning in a region had a direct relationship with this conversion coefficient (P<0.05). Conclusion The variations observed in the conversion coefficients and their dissimilarity among different regions of Iran may be due to a variety of fundamental factors of which literacy and culture are of important factors. Objective To calculate couple-year of protection (CYP) by conversion coefficient (F) of tubectomy and vasectomy in urban and rural regions of Iran. Methods A total of 103 450 married women aged 10-49 years in 2005 across urban and rural regions of Iran were sampled by multi stage cluster sampling. The Data were collected by household survey and direct interview and analyzed by STATA8.0 software and survey analysis commands. Results Mean age of the women at the time of tubectomy estimated 31.9 years and conversion coefficient of tubectomy was 17.1 ± 0.1. Mean age of women at the time of her husband vasectomy estimated 31.48 years and its conversion coefficient was 17.5 ± 0.1. Cluster analysis defined different regions of Iran on the basis of evaluated conversion of tubectomy and vasectomy which both of them presented seven clusters. Literacy of women and total coverage of family planning in a region had a direct relationship with this conversion coefficient (P <0.05). Conc lusion The variations observed in the conversion coefficients and their dissimilarity among different regions of Iran may be due to a variety of fundamental factors of which literacy and culture are of important factors.