To study the including rhizobium treatment (strain numbers of 133, 116 & combination of them) along with 100% nitrogen fertilizer application and a check (no inoculation & no fertilizer) on certain agronomical and physiological traits of three common bean cultivars (viz. Bahman, Darkhshan & Sayiad) a field experiment was performed at research station of University of Tehran (Karaj-Iran) in 2010, using a randomized complete block design in a factorial arrangement with three replications. The characteristics such as seed yield, pods per plant, seeds per pod, 100 seed weight, seed protein percentage, chlorophyll a & b and leaf protein were measured. Inoculating rhizobium strain 116 produced the highest bean grain yield (44.9 g/Pl.). Bahman cv. with inoculating rhizobium strains of 133+116 gave the highest pods per plant (57.9 pods/pl.). Sayiad cv. with check (no inoculation) and inoculating rhizobium strains of 116 produced the highest seed protein percentage of 28.07 & 28.05% as compared to other treatments, respectively. Considering the significant interaction effect of bean cultivars and rhizobium treatment for all the characteristics, the mean comparison was used to determine the best treatment combinations. Overall, the combination of Sayiad cultivar with rhizobium strain of 116 showed the highest seed yield and traits, which could be as the best combination treatment for replacement of nitrogen fertilizer. A good key for presentation of plant performance in fixing nitrogen would be leaf protein content, for which the treatments with higher chlorophyll content had the best possible growth condition. The bean Darakhsan cv. treated with rhizobium strain of 116 produced the highest leaf protein (27.68%) as compared to other fertilizing treatments; similarly produced the highest chlorophyll content as it was treated with rhizobium strain of 133.