This article analyses the impact of the past of the Portuguese social security system on possibilities for reform. First, some of the most relevant features of the Portuguese welfare state are compared with the Southern European model. Its particularities are emphasised suggesting that it may not be subject to the same path dependency. Then an historical description of its most relevant moments is made indicating the alternation of different welfare models in its policies. This gives rise to discontinuities that have been constant through its history and determined by some of the most permanent features of state and society.