This study focuses on the relationship between the military reforms of the New Granada in the 18th century and on military administration, including its expenses. Furthermore, it analyzes the relationship between the fiscal and militar administration and the defence objectives of the Viceroyalty of New Granada. Àe main idea is to set up the political and administrative reasons why the New grenada became one of the most important geopolitical territories in the Caribbean during the 18th century. It also analyzes connections between military reforms and taxes.