Two whitefly species, Aleurotuberculatus jasmini Takahashi and Dialeurodes kirkaldyi (Kotinsky) were found infesting Arabian jasmine shrubs, Jasminium sambac at the Botanic Garden of Faculty of Agriculture, Ain Shams University, Shoubra, Qalyubiya, Egypt. To obtain basic ecological data for both species, samples of Arabian jasmine leaves were conducted every ten-day intervals throughout one complete year (January to December 2004). Seasonal fluctuations of alive total population, nymphs and adults (empty exuviae) of the both species indicated that the D. kirkaldyi was more dominant one than A. jasmini throughout the tested year. Three periods of seasonal abundance for both species were established. Three annual field generations were estimated for D. kirkaldyi, which lasted 170, 90 and 100 days, respectively. While A. jasmini passed throughout five annual field generations, which lasted 80, 80, 70, 60 and 70 days, respectively. The effects of nine ecological factors (7 physical +2 biotic) on the population dynamics of alive nymphs population for both species were estimated. Each factor gave variable effects for both species while the combined effects of these nine factors were responsible as a group for about 74.2% and 95.5% of the changes in nymphal population densities of D. kirkaldyi and A. jasmini, respectively.