This papers? objective is to examine the effects that labour market institutions (LMI) have on the unemployment in the short- and the medium run throughout the new Keynesian NAIRU theory, but also to make a comparison with the postkeynesian capital stocks? effect on the unemployment. Thus, it is this papers? main objective to study the economic effects that LMI, capital accumulation and varied macroeconomic shocks might have on unemployment. The paper uses econometric regression models as a methodological benchmark in order to estimate each independent variable?s level of significance and to approximate the effect each have on the dependent variable.