Population dynamics of pink bollworm on cotton was studied through male moths captured in the traps baited with sex pheromone ‘gossyplure’ and by its damage to the flowers and green bolls during 1978 and 1979 crop seasons. The number of pink bollworm male moths captured in traps were low up to August. Maximum moth population was recorded from the second fortnight of September to the second week of November. The population started declining after the first fortnight of November, indicating that most of the larvae had entered diapause due to the short photoperiod and low temperature. Incidence of pink bollworm on flowers was high up to the last week of August, after which it declined. While on green bolls its infestation started in the beginning of August and continued to increase up to the end of the season. A linear and highly positive correlation was found between the male moth catches in traps and the larval damage in flowers and bolls (r = 0.84 and 0.95 in 1978 and 1979 crop seasons, respectively).