["Economics of Transition and Institutional Change, EarlyView. ", "\nABSTRACT\nThis paper investigates the demographic consequences of militarisation in transition economies by analysing the effect of armed forces size on fertility rates across 15 post‐Soviet countries from 1992 to 2022. Using panel fixed effects and two‐stage least squares (FE‐2SLS) with U.S. military aid as an instrument, we find that military expansion exerts a significant negative impact on fertility. Mediation analysis suggests that societal anxiety serves as a key channel. A case study of Russia highlights how sanctions and conflict further accelerate fertility decline. The findings underscore how institutional legacies of conscription shape demographic outcomes in transitional settings.\n"]