Reanalysis of a standard set of data for 16 nations has brought new insights into the leading issues of comparative social mobility. The reanalysis provides considerable support for the Featherman-Jones-Hauser hypothesis, which claims that there is convergence in mobility processes once conditions of occupational supply and demand are controlled. The hypothesis is modified, however, in two respects: First, it is qualified by the suggestion that uniformity in mobility regimes is not limited to highly industrialized societies but may apply equally to less developed societies; and second, it is elaborated through specification of the structure of the shared mobility regime. Properties of mobility shared by the 16 countries considered are: (1) symmetry of exchange between occupational strata; (2) equality of mobility chances off the main diagonal; (3) severe immobility at the two extremes of the occupational hierachy; and (4) considerable mobility in the middle of the hierachy. These findings of basic similarity do not preclude findings of deviation from the common mobility regime, which seem to be at least as much a consequence of political organization as of economic development. The effects of political and economic variables on mobility processes are more complex than commonly supposed because they differ across occupational strata. (Author/CMG)