This research aimed to isolate and characterize cyanobacteria that have the ability to grow in the polluted soil with insecticide and evaluation of their efficiency in fixing nitrogen and dry weight.   Cyanobacteria were isolated from samples of soil site polluted with insecticides in Kafr El- Sheikh, Governorate. Cyanobacteria were purified by different purification methods. Twelve cyanobacterial isolates were identified according to standard methods based on cultural and morphological characters of cyanobacteria as following: color of culture, morphology of thallus, vegetative, reproductive cells and heterocyst.  Heterocyst from isolates of cyanobacteria were observed in Anabaena sp., Nostoc sp., Oscillatoria sp. and Chroococcus sp. Nostoc sp. was of the highest frequency (66.6 %) among the isolated cyanobacteria.  While, Oscillatoria sp. and Chroococcus sp. were less frequency (8.3%). Dry weight and nitrogen fixation of cyanobacteria were determined for efficiency evaluation of these isolates. The superior cyanobacterial isolates, which isolated from soil polluted withinsecticides were identified by 16S rRNA as Nostoc muscorum  and  Anabaena oryzae.