Technical Abstract: Ascochyta blight caused by the fungus Ascochyta rabiei (AR) depresses chickpea production in Pakistan and worldwide. Thirty two AR isolates representing six geographical regions of Pakistan was compared with a US AR population for frequency of mating types and genetic variation. Mating type results showed that the Pak-population had a skewed (3 Mat1-2 : 1 Mat1-1) distribution, whereas the US-population showed a 1:1 distribution. The uneven distribution of mating types indicates that sexual reproduction among the Pak-isolates is rare or not occurring due to either unavailability of both mating types or lack of conducive environment. Genetic variation at six microsatellite loci was assessed and each isolate was assigned to a microsatellite haplotype. Population structure of the isolates was inferred using Bayesian analyses implemented in the Structure software, which differentiated isolates into three distinct clusters, two clusters in Pakistan and one in the US. However a few isolates from the US shared the same genetic background with one cluster of the Pak-isolates, providing a link of inter-continental migration of the pathogen. Additionally, the two clusters of Pakistani isolates are not strictly linked to the geographic locations in Pakistan, suggesting frequent gene flow of AR among different locations.