The present investigation was directed to study the Occurance and seasonal abundance of the pink bollworm, Pectinophora gassypiella (sanders)in cotton fields during 2005 and 2006 at Kafr EL-Sheikh and Dakahlia Governorates. The effect of prevailing climatic factors on flight activity of using pheromone traps during two successive cotton season indicated that P.gossypiella had three generations with three sharp peaks on cotton during the period started early in June and extended till the end of September  The combined effect of the prevailing temperature and relative humidity were  responsible for (40.5 ,38 ) and (13.7, 11.1) at Kafr EL-Sheikh governorate of the changes in amole moths population during 2005 and 2006, mean while, Dakahlia Governorate responsible for (8.3,23.2) and (36.7, 10) of the changes of the population and moths respectively. Larval population and boll infestation started during early July and increased  progressively till the end of the season.