The present work was carried out to study the number and dura­tion of spiny bollworm, Earias insulana (Boisd.) field generations during three cotton growing seasons of 1993, 1994 and 1995 at Gharbia, Kafr El-Sheikh Governorates and for two tested seasons of 1993 & 1994 at Beheira Governorates. To facilitate the graphical and numberical presen­tation of the data, each locality was discussed separately for the three years combined. The present results revealed the presence of six over­lapping generations during the whole investigation period in each of the three tested localities were estimated.