Resumen La presente investigacion centra su analisis en el gasto de defensa y seguridad (GDS) empleando el uso de la disciplina de la economia de defensa, la cual estudia las politicas de seguridad mediante la aplicacion de herramientas elaboradas por la economia como son los metodos de analisis macroeconomico y microeconomico, optimizacion estatica -dinamica, teoria de juegos y econometria. El interes por el estudio de la defensa y la seguridad es reciente y ha cobrado auge debido a la insercion de Colombia en el escenario internacional, a causa del conflicto interno que persiste en el pais, y que ha llegado a ser parte de la agenda internacional. El sector defensa no ha tenido tradicion tecnocratica, y el campo de investigacion es incipiente, el presente trabajo presenta una aproximacion al estudio del gasto en defensa y seguridad (GDS) entre 1950 – 2006, donde se comprobara como este agregado macroeconomico se mantuvo por debajo del promedio regional a traves del siglo XX. El GDS de este pais no se correlaciona con el conflicto interno y la trayectoria que sigue es aleatoria; la politica de seguridad y defensa es producto de eventos coyunturales y no el fruto de una planificacion del primer bien publico que debe entregar un Estado a sus ciudadanos, de esta forma la inferencia que este ha tenido sobre hacienda publica, no responde a una politica publica estatal. Abstract The present investigation centers its analysis in the cost of defense and security (GDS) using the use of the discipline of the defense economy, which studies the policies of security by means of the application of tools elaborated by the economy as they are the methods of macroeconomic and microeconomic analysis, static optimization - dynamic, theory of games and Econometry. The interest by the study of the defense and the security is recent and has received height due to the insertion of Colombia in the international scene, because of the internal conflict that persists in the country, and that has gotten to be part of the international agenda. The sector defense has not had technocratic tradition, and the Investigation field is incipient, the present work presents/displays an approach to the study of the cost in defense and security (GDS) between 1950 - 2006, where it will be verified as this one macroeconomic aggregate stayed below the regional average through century XX. The GDS of this country is not correlated with the internal conflict and the trajectory that follows is random; the policy of security and defense is product of conjuncture events and not the fruit of a planning of the first public good that must give a State to its citizens, of this form the inference that this it has had on public property, does not respond to a state public policy.