The Karyomorphology of all taxa of section Bucerates Boiss. genus Trigonella L. (Leguminosae) were made using Image Analysis System. The chromosome numbers of 14 taxa of Trigonella (2n = 16), T. fischeriana Ser. and T. monantha C.A.Meyer subsp. noeana (Boiss.) Hub.-Mor. (2n = 14), T. monantha C.A.Meyer subsp. monantha Verz. (2n = 16, 28, 30) and T. orthoceras Kar. & Kir. (2n = 16, 46) were counted. B chromosomes were observed on T. arcuata C.A.Meyer. and there were two chromosomes with a satellite in T. crassipes Boiss. In the section Bucerates, 12 taxa of Trigonella showed tetraploidy, with 2n = 32 and two taxa of Trigonella had hexaploidy (2n = 48). The range of chromosome length ranged from 3.26 mu m to 0.56 mu m. Whereas T. orthoceras had the longest chromosome length, T. monantha subsp. monantha had shortest.