Karyotype analysis of Macrotyloma uniflorum (Lam.) Verdc. (Family: Leguminosae; Sub-family: Faboideae; annual herb, potential uses—nutraceuticals, forage and food for humans) revealed 5 (2n=20; 4A_m+2B^sc_sm+2C_sm+2D_sm+10E_m) morphologically distinct chromosome types. The karyotype showed a prevalence of chromosomes with median primary constrictions. Satellites were associated with the short arm of 2B-type chromosomes. Chromosome length in the complement varies from 1.26 to 2.41 μm. The karyotype was symmetric in nature (TF%=43.11). The meiocytes had 2n=20 chromosomes always with an average of 9.96II+0.08I per cell at diakinesis and metaphase I. Formation of 10 II was predominant (95.83%). All anaphase I cells were cytogenetically balanced (10/10). About 66.67% diakinesis and MI cells showed secondary association of chromosomes and the chromosomes assorted themselves into variable groups of 4 (4.69%), 5 (6.25%), 6 (23.44%), 7 (64.06%) and 8 (1.56%). Out of 24 different types of associations among the group classes, 2II(3)+1II(4)—46.88% (7 group class) was the most frequent. Secondary polyploidy has been attributed as the possible cause of secondary association of chromosomes and the basic chromosome number for the species is suggested to be x=7.