Abstract: Two isolates of Ascochyta rabiei (Pass) Lab. derived from single spore cultures representing the most and least aggressive nature were studied separately and in combination for pathogenic aggressiveness on sixteen chickpea varieties. A great deal of variation was observed in the pathogenic reaction of isolates for inducing disease development. The cultural traits, radial growth and pycnidial size, were also significantly different for the two isolates. Similarly, a significant difference between chickpea genotypes was observed for their response to isolates regarding disease development. Five varieties, C-727, C-44, Noor-91, Punjab-91 and ILC-263 revealed high degree of susceptibility and are suggested to be used as susceptible checks for screening experiments. Two other genotypes, Dasht and Balkasar showed high degree of tolerance to both the isolates when applied separately or as 1:1 mixture. The aggressiveness of mixture of two isolates was reduced to the level of least aggressive isolate instead of having synergic effect for blight development.