SDS- PAGE electrophoresis of leaves, seeds and chloroplast salt and alcohol soluble proteins were studied in 9 Medicago species. Certain bands could be easily used by any researcher to identify species under study or their hybrids. A total of 68 alcohol and salt soluble protein bands (16 monomorphic and 52 polymorphic) were used to estimate the genetic distance among the species. These species were clustered together between around 0.1 to 0.4 level of distance, with a mean value of 0.296, showing that the genetic dissimilarity between Medicago species is smaler than their similarity (1-0.296=0.704). Cluster analysis differentiated 9 species in 4 groupes: 1) M.sativa 2) M. lupulina; 3) M. radiata and M.minima and 4) M. orbicularis , M.rigidula M.scutellata , M.truncatula and M.littoralis. The two latest species were the most similar but the most dissimilar one was alfalfa (M.sativa). Some differences observed, with respect to common classification of Medicego species were discussed.
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