This publication includes all data on superconductive materials intercepted through March 1975. Data on the bulk elements have been critically evaluated, and values on alloys, compounds, and other forms have been selected and condensed to indicate the probable value and spread of values observed. Proven non‐superconductors have been noted. Conflict in data values has been noted. All data have been keyed to the literature in one or more of the tables. Special subdivisions are presented for superconductive materials with organic constituents and for those based on semiconductive materials. The properties presented are superconductive critical temperature, critical magnetic fields, material state and composition including crystal‐structure type where noted, a key to thin‐film forms, and the presence of thermodynamic data (generally the electronic specific heat, &ggr;, and Debye &Vthgr;). High‐magnetic‐field superconductors are noted with listing ofHc1,Hc,Hc2, andHc3plus the temperature of observationTobs.