Two‐dimensional gel electrophoresis of shoot proteins was used to study the relationships between Triticum, Secal, and Hordeum. A high level of polymorphism was found among the 1275 spots scored: only 198 spots were found common to all. But, under the hypothesis that only allelic variations were observed, the mean number of alleles per locus was only two. Phenograms were built from different distance indices. All of them showed Triticum genomes A and D close to each other, Hordeum, far from the Triticum cluster, and Secale at an intermediate position. A discussion on the use of various distance indices is presented.