Aflatoxin contamination in groundnut seeds caused by Aspergillus flavus hampers international trade adverselyand affects the health of consumers of groundnut and its products, hence present study conducted with an objective to findout resistant sources in groundnut for in vitro seed colonization. A total of 72 groundnut germplasm lines were screened forin vitro seed colonization by A. flavus. None of the cultivar was found to be completely free from A. flavus colonization.Seed colonization severity ranged from 1.22 to 4.00 on 1-4 scale used for scoring after eight days of incubation. Minimumcolonization (1.22) was recorded on SB-T10, however cultivars ICGV-15138 (1.78) and ICGV-15124 (2.00) were found onpar with resistant check J-11 (1.78), while 47 cultivars showed colonization severity ranging from 3.72 to 4.00 and werefound to be not significantly deviating from the susceptible check JL-24 (4.00). Remaining 20 lines showed intermediatelevel of resistance to seed colonization as indicated by the colonization severity ranging from 2.61 to 3.61