The substantial resources devoted to warfare in modern times might explain the increasing relevance that military spending has acquired in social sciences. In this regard, the so-called defence economics has extensively studied the main determinants of military spending and its main consequences in terms of economic performance and institutional transformations. However, one of the main problems for comparative analysis on the causes and effects of military spending is the lack of long-term homogeneous and comparable data in international panel datasets. This paper contributes to fill in this gap by providing new military spending data on Spain from 1850 to 2009 based on NATO methodological criterion. It provides total military spending estimates as well as economic and administrative disaggregated figures for most of the period. These data allow reliable international comparisons while also providing new quantitative evidence to better understand the military history of Spain in modern times.