Field experiments were conducted at sugar beet fields at four districts (Kafr El-Sheikh, Qualleen, El-Riad and El-Hamoul) of Kafr El-Sheikh Governorate during three successive seasons, 2007/08, 2008/09 and 2009/10 seasons. The experiments aimed to monitor population fluctuations of cotton leafworm larvae on sugar beet planted on August 1^st as first cultivation. The reductions in plant stand due to Spodoptera littoralis Boisd attacks were computed, and the correlations between this insect pest and each of predators and some weather factors were calculated. The highest population density of S. littoralis larvae was found during September and October with densities of 81.00 – 113.25, 95.00 – 126.25 and 119.25 – 18350 larvae/10 sugar beet plants in 2007/08, 2008/09 and 2009/10 sugar beet seasons, respectively. The high infestation by cotton leafworm synchronized with high temperature prevailing in September and October as compared with those prevailing in November and December. The coccinellid, true spiders and Chrysoperla carnea Steph. populations were high during September. The plant stand was heavily reduced due to S. littoralis attacks with values ranging between 93.67 and 94.52% at the four districts. Correlation coefficient values were highly significant between S. littoralis larval population and each of coccinellid and C. carnea populations.