pink bollworm, Pectinophora gossypiella (Saunders) infestation on Bt cotton is a major concern to cotton production in india. the genetic diversity and phylogeographic structure of the insect in light of PBW resistance needs to be revisited. The objective of this study was to identify different haplotypes of pink bollworm and their distribution in India. To achieve this we studied the population structure in 44 cotton growing districts of India. The partial mitochondrial COI sequence analyses of 214 pink bollworm populations collected from 44 geographical locations representing 9 cotton growing states of India were analysed. Genetic diversity analysis exhibited presence of 27 haplotypes, among them Pg_H1 and Pg_H2 were the most common and were present in 143 and 32 populations, respectively. Distributions of pairwise differences obtained with partial COI gene data from the overall Indian populations are unimodal, suggesting population expansion in India. Significant neutrality test on the basis of Tajima' D and Fu's Fs presented a star-shaped haplotype network together with multiple haplotypes. The unimodal mismatch distribution, rejection of neutrality test with significant negative values supported the theory of demographic expansion in cotton pink bollworm populations in india. Genetic data not only provides us with a perspective of population genetics, but also that the two populations of pink bollworm, those occurring early in the season are genetically close to the late season populations with respect to their partial CO1 region. Resistance to Cry toxins does not seem to have had an impact on this region of the mt DNA in populations of pink bollworm.Cotton is one of world's most essential fiber crops having global significance, cultivated in tropical and subtropical regions of more than 70 countries 1,2 . In India, cotton is mainly cultivated in three distinct agro-ecological zones (North, Central and South) 3,4 . Cotton is cultivated on an area of 12.43 million ha with average productivity of 505.46 kg/ha in India during 2017-18 5 . Several biotic and abiotic stresses are constraints in cotton production including the bollworm complex and sucking pests 6 . Among the bollworm complex, pink bollworm (PBW), is one of the major damaging insect pests of cotton with an extensive range across India leading to severe loss to cotton production 7,8 .Pink bollworm has become apparent as a threat to cotton cultivation in south and central cotton growing zones of India where the pest has developed resistance to Cry1Ac and Cry2Ab expressing cotton also developing resistance to insecticides and infesting late season cotton 8,9 . The PBW is assuming a major pest status even in some regions of northern India where there are ginning and oil extraction units which are procuring cotton seeds from central and south Indian cotton states where PBW has demonstrated resistance to Cry toxins in the field. So there is possibility of resistant pink bollworm infesting Bt cotton in North India through movement of seed. The evolution of...