Field experiments were conducted at farm of Sakha Agricultural Research Station, Kafr El-Sheikh Governorate during 2005, 2006 and 2007 cotton growing seasons to study the population abundance of Bimisia tabaci(Genn.) on cotton in relation to common associated predators (Coccinella spp., Scymnus spp., Chrysoperla carnea, Syrphus corellae, Orius spp. and true spiders) and some prevailing weather factors (temperature, relative humidity and wind speed). Concerning the associated predators, their total population fluctuated and recorded three peaks of abundance during, August and September (2005 season) and four peaks during 2006 and 2007 seasons. The combined effect of weekly mean of total predators, daily mean temperature, relative humidity and wind speed was responsible for 81.44, 82.19 and 95.42% of change in the population of whitefly B. tabaci in 2005, 2006 and 2007 cotton growing seasons, respectively. Results obtained could be summarized in the following points: - Four peaks of abundance were observed for B. tabaci (Genn.) during the period of study from May to September for each season. - Maximum number of B. tabaci took place during July and August for three tested seasons with a mean of 628, 890 and 4188 individual/50 cotton leaves and 3954, 3920 individual/50 cotton leaves (2007 season), respectively.