Abstract Background: There is further evidence of breast feeding benefits for mother and infant health. In some regions of the world the rate of exclusive breastfeeding during the first 6 months of infant’s life has been decreased. The most important factors associated with the problem are socio-economic variables such as maternal age, mother’s employment status, level of education, and infant’s birth interval from previous or next child. Materials and methods: This analytic cross-sectional study was conducted on 340 mothers and their 6-12 months old children referring to Khorramabad health centers to achieve their children primary health cares from March 21st, 2006 to March 21st, 2007. Variables such as maternal age, mother’s employment status, delivery status, mother’s education, child birth rank, infant’s gender, and infant’s birth interval from previous child were investigated. The association between the exclusive breastfeeding failure and the variables were tested by χ2, Fisher exact test, t-test, Mann-Whitney, Pearson coefficient, and Kruskal-Wallis test. Results: Out of the 340 samples, 151 mothers (42%) had given birth with cesarean section, 57 of the cases were employed mothers compared with the 283 unemployed ones. In addition, 185 and 155 children out of the 340 samples were boys and girls respectively, and 10 were twins. The prevalence of exclusive breastfeeding for the first six months of life was 79.1% (268 cases) in comparison with the 20.9% who had failed to be exclusively breastfed. Statistically significant relationships were found between the failure of exclusive breastfeeding with mother’s employment status, maternal education, and cesarean delivery. A reduction in child’s growth was the main reason reported by the mothers for the exclusive breastfeeding failure. Conclusions: In this study, the failure of exclusive breastfeeding in the first 6 months of life was 20.9%. According to the findings, at least a 6-month period of maternity leave is suggested for employed mothers. Additionally, providing appropriate places for mothers to breastfeed their infants as well as a reducing their working hours are highly recommended.