The substantial variation in the melting behavior of the 123 (RE) high‐Tcsuperconductor (HTSC) phase Re1Ba2Cu3O6.5+&dgr;with substitution of different RE’s has been noted and partially studied before. Because of the enormous practical importance of the melting points in the processing of this major HTSC compound (e.g., in melt growth or regrowth, use as crucibles or melt substrates, non‐melting dispersoids, etc.), we have undertaken an operational study of the softening and melting behavior for all accessible RE elements forming a superconducting 123 phase; we report this study here.