Fertility rate as an effective factor in population change is of great importance in all societies. In this article, using the information of household income and expenditure plan in 2017 of Iran Statistics Center and using the Poisson method in Stata software, the effect of women's employment on fertility has been investigated. The estimation results show that women's employment has a negative and significant effect on fertility; in such a way that their employment reduces the size of the household by an average of 7%. Age and education variables also have a negative effect on the household dimension. Although the coefficient related to the income variable is positive and significant, its smallness indicates a very insignificant effect on the household dimension. The variables of educational expenses and religious expenses also have a positive and very strong effect on the household dimension. The virtual variable of urban and rurality of the household did not have a significant effect on the size of the household; therefore, it seems that the larger size of rural households is explained only through other variables of the model, especially the employment of the woman and her education.