This paper analyses some determinants of urban violence in seven major Colombian cities. The empirical research is intended to explore variations in violence across these Colombian cities and the influence of these variations on Colombia's economic development. In this study, several econometric data panel models and various estimate types are applied to control heterogeneity across the cities and to address endogeneity problems among the explanatory variables. The results show that education, poverty, inequality and the labour market are strong predictors of homicide rates in the seven Colombian cities. The results also demonstrate that city-level homicide rates depend on the city's level of development and the tendency of urban violence to persist over time. The findings thus demonstrate that factors such as inequality, poverty, education and the labour market influence urban violence, thereby generating negative effects on Colombia's economic and social development.