Symbiotic effectiveness of 19 indigenous and two exotic (USDA 2426 and USDA 2431) strains of lentil Rhizobium belonging to different phage-sensitive and phage-resistant groups was compared under axenic condition. Four strains (USDA 2431, BHULR 104, BHULR 113, and BHULR 115) sensitive to different phages were found significantly superior over others in terms of nodule number, acetylene reduction activity, and total dry weight per plant. Inoculation response of these strains was then evaluated on six lentil cultivars under field condition. A significant symbiotic interaction between rhizobial strains and lentil cultivars was observed. Grain yield enhancement was noticed by the compatible interaction of lentil cultivars HUL-57, L-4147, K-75, and PL-4/DPL-15/DPL-62 with rhizobial strains USDA 2431, BHULR 104, BHULR 113, and BHULR 115, respectively. The authentication of rhizobial strains was accomplished through 16S rDNA sequence analysis. All rhizobial strains had close matching with R. leguminosarum bv. viciae strains. The results have shown that phages can trustfully help selecting out the symbiotically efficient most rhizobial strains for advantageous use with lentil cultivars, in order to strengthen the BNF-based future lentil breeding programs.