ATRAZINE is the most extensively used herbicide that restrains photosynthesis of broad leaf and grassy weeds. In consequence of ground and surface water contamination with atrazine, humans and wildlife might be at risk. In the current investigation, an atrazine-degrading bacterium was isolated from agricultural drainage ditches (Fayoum, Egypt) using enrichment technique. According to the morphological, biochemical and 16S rDNA gene sequencing, the bacterial isolate was identified as Ochrobactrum oryzae. Using atrazine as sole carbon and nitrogen source, a pure culture of O. oryzae was grown in minimum media. The impact of atrazine concentration as well as temperature and pH on the bacterial growth and atrazine degradation rate was studied. The greatest potential for atrazine degradation (83.5%) was attained at concentration 400 ppm of atrazine within 9 days at pH value 9.0 and temperature 30°C. Consequently, O. oryzae can be applied conveniently for the cleanup of agricultural wastewater contaminated with high levels of atrazine.