PPP as an innovative public procurement tool for the provision of public services and/or the construction of public works are nowadays globally presented, on the one hand as the newest and most important, on the other hand as the most advanced and flexible form of a lower-intensity privatisation method that indicates the withdrawal-retreat of the State from its public-character duties and functions. PPPs are therefore a species of privatisation having already developed distinctive features in comparison to the various forms of the privatisation phenomenon. However, both techniques are delimited by certain constitutional limitations on the private-sector involvement in public functions and administrative activities. The international experience gained so far from the implementation of various privatisation programmes worldwide stresses the fact that privatisation cannot always be expected as an easy and fast process that can rapidly be remunerative for the financially-ailing governments, since in practice it may result in a rather protracted and long-term procedure so as to attract a solid investment interest on the part of the private sector. Contrary to full-outright privatisation, which may meet explicit constitutional barriers, the promotion of a privatisation doctrine through the recourse to PPPs as a lower-intensity privatisation method, can sometimes realise the attraction of the private sector to invest in areas where his full involvement would in any case infringe the Constitution.