The causes of internal conflicts are not easy to identify, and in order to understand its dynamics it is important to determine the factors that influence its persistence. The appropriation of economic resources has been identified as a cause of the conflict; however, asset appropriation may not be the main motivation for armed groups. On the contrary, it may be seen as a means of financing, which influences the conflict’s persistence. In Colombia, land appropriation has been a recurrent strategy for illegal armed groups in order to increase their territorial control and the institutional weakness when defining property rights may facilitate illegal appropriation of these assets. The hypothesis presented in this work is that the informality of property rights positively influences the armed groups’ decision of attacking and, therefore, influences the conflict’s intensity. In order to prove this hypothesis, an econometric model is proposed, which explains the conflict’s intensity through economic, social and institutional indicators at a municipal level. The results suggest that with a greater formality in property rights, the conflict’s intensity decreases.