Nowadays, using sustainable dyeing process has become a necessity, but does not meet performance requirements. Application of biomordants was recommended to enhance the quality of dyeing. Tannin-based biomordants appeared advantageous in green dyeing; meanwhile, unconditional affinity towards fibers of different types has attracted the attention of researchers. We introduce the idea of using combination of natural mordant as a new technique for sustainable dyeing of wool and a model natural fiber. In this study, Iranian madder was used as green dye and Yellow Myrobalan (YM) and Black Myrobalan (BM) employed as biomordant. FTIR-ATR spectra of the washed, mordanted, and mordanted-dyed wool fibers confirmed appropriate bonding among wool fibers, green mordant, and dye molecules. The superior color strength of wool fibers dyed with 4 %YM+6 %BM and 40 % madder was featured by K/S value of 35.77 and was obviously higher than that of madder by sumac, 9.5. Fastness properties (light, wash, and rub fastness) of wool dyed with combination of YM and BM were good.