This work was carried out to investigate the population dynamics of black scale insect Chrysomphalus aonidum L. on leaves and fruits of Navel and Balady orange at Tukh  and Qalub districts in Qalubia governorate during two successive years from September 2015 to August 2017. The obtained data show that, the highest numbers of  C. aonidum were recorded in October with total numbers 185 & 195 adult on Navel  and Balady orange at average temperature 23.7 C^° and relative humidity 74.4% in the first year and 196 & 213 insect in the second year when average temperature and relative humidity were  23.1 C^°  and  75.9% , respectively. Meanwhile , the highest number of  Ch. aonidum   at Qalub district was recorded in October with total number 160 and 169 adult on Navel and Balady orange at average temperature 25.8 C^° and relative humidity 60.1% in the first year while , in the second year , the total numbers of  C. aonidum   were 174 & 192 adult on Navel and Balady orange at average temperature 25.4 C^° and relative humidity 62.4%. Also, data revealed that the population of black scale insect, Ch.aonidium on Navel and Balady orange trees was positively significant with average of temperture  and nonsignificantly negatively with relative hummidity  .