Using longitudinal panel data from the Western Chitwan Valley of Nepal, this study examines the impact of the use of modern farm technologies on fertility transition--specifically, the number of births in a farm household. Previous explanations for the slow pace of fertility transition in rural agricultural settings often argued that the demand for farm labor is the primary driver of high fertility. If this argument holds true, the use of modern farm technologies that are designed to carry out labor-intensive farm activities ought to substitute for farm labor and discourage births in farm families. However, little empirical evidence is available on the potential influence of the use of modern farm technologies on the fertility transition. To fill this gap, the panel data examined in this study provide an unusual opportunity to test this long-standing, but unexplored, argument. The results demonstrate that the use of modern farm technologies, particularly the use of a tractor and other modern farm implements, reduce subsequent births in farm households. This offers important insight for understanding the fertility transition in Nepal, a setting that is experiencing high population growth and rapidly changing farming practices. (Contains 2 tables.)