The debate points out the different assumptions connected to the various patterns of working time reduction. The focus is upon two principal models, which are at present under discussion at a sociological and political level. The first model regards working time reductions as an instrument to face particular situations of occupational crises or reorganization within the enterprise. The second model, on the other hand, regards generalized and consid¬erable working time reductions as a keystone to re-shape both the value of work and the aspects of the social structure involved. These models engender relevant effects at a legal level, particularly with respect to the relationships between sources of law, such as statutory instruments and collective bargaining: the perspectíves and the limits of the solutions put forward by the italian and the EEC legislation on this point are compared with the most con-vincing proposals within the Italian doctrinal panorama