Electrophoretic seed protein patterns of 18 samples belonging to 14 species and 4 sections of Lathyrus are treated by principle component analysis (PCA). The morphological ground and karyological structure data of these samples are also discussed in the light of sectional and groups delimitation. The species under study of section Cicercula are separated into 3 groups and L. hirsutus referred to the most primitive species within Lathyrus species. This agrees with their previous grouping delimination based on morphological characters and with chromosomal features such as karyotype structure. L. aphaca referred to the most advanced species in this genus, which agrees with the modification of this morphological characteristics and reduction in chromosome criteria. Section Nissolia hasan intermediate position between section Cicercula and section Aphaca.