Gossypium hirsutum cultivars Deltapine (DP) Acala 90, DP 120, DP 77, DP 61, DP 41, DP 20 and McNair 235 did not vary in innate susceptibility to aflatoxin contamination of cottonseed via A. flavus colonization of simulated pink bollworm exit holes. Intercarpellary membranes of all cultivars were only partially effective at preventing fungus spread from damaged into undamaged locks. The results provide baseline values for interpretation of field observations and cultivar efficiency in restriction of A. flavus boll infections.