Root nodules infection of different faba bean (Vicia faba L.) cultivars by bean yellow mosaic virus (BYMV) and the effect of the disease on the specific activity of the nodule are reported. The disease reduced the fresh weights of tops, roots, root nodules and induced premature nodule decay and/or nodule drop. Six local cultivars: Barekat, Iranshahri, Saraziri, Aljazayeri, Shakhbozi and Zohre of faba bean were selected and inoculated with BYMV under greenhouse conditions. ELISA test (DAS-ELISA) with specific BYMV antibody (DSMZ AS0471) demonstrated that nodules from faba bean plants which had been inoculated with BYMV contain the virus too. Susceptibility of different faba bean cultivars was analyzed by ELISA. The relative accumulations of BYMV in the nodules were evaluated by mean ELISA values (OD405) of BYMV. There was significantly difference in cultivars. Cultivars went more susceptible from Barekat to Iranshahri, Saraziri, Aljazayeri, Shakhbozi and Zohre. High susceptibility of Zohre was confirmed in a second experiment including visual evaluation and DAS ELISA. Analysis by IC-RT-PCR revealed the presence of the virus in all nodules and amplified a 970 bp fragment with specific designed primers (Forward primer (5'-CT(AC) CA(AG) ATG GAG AA(CT) CC(CT) GC 3') and Reverse primer (5'-CCA AAG TTC CAA TCA CCA CC 3').