Studies on different countries show that the behavior of the unemployment rate is closely linked to the history of the country concerned. It is not easily explained by the present level of aggregate demand or changes in the supply of labour. Traditional models based on the Phillips curve do not take this dependence into account. The concept of hysteresis is an attempt to separate inertia and the degree of inertia in the unemployment rate from its determining factors in macroeconomic analysis. The results, in the case of Colombia, show a high level of inertia in Bogota and Medellin, but much more flexibility in Cali and Barranquilla. The absence ofeffect of monetary policy and the differentiated impact of investmentand exports on a regional basis can both be clearly appreciated.