Now being one of the 10 most important urban centres, Leuven (Louvain) provides a good case to study the determinant elements that have inspired the policy of mergers of communes in Belgium in 1975. Technocracy, consultation of the municipal councils concerned, preferences of the population, the opposition in parliament have all had very little or no influence at all on the eventual decision-making.On the contrary, specific pressure groups, supervision authorities, the extent to which one tried to anticipate the 1976 local elections, and the power position of the majority parties have substantially infiuenced the merger map. Thus, these decision-making elements contain a considerable distortion - in terms of actual realization - of the official ideology behind the mergers, i.e. to make the municipal executive power more efficient.