A Ph.D. thesis at the Faculty of Science at the University of Basrah discussed the (biosynthesis of Ag and CuO NPs by environmental bacteria with some medical applications), and the researcher's thesis (Hasan Ghali Abdulhasan) aimed to investigate the biological activity of Ag and CuO NPs synthesized by bacteria isolated from oil field reservoirs, and included the isolation and molecular identification of bacteria obtained from produced water samples of Al-Halfaya oil field reservoirs at east of Amarah City, as well as the biosynthesis and characterization of the NPs produced by these bacteria. The study also included the evaluation of the effects of Ag and CuO NPs against multidrug-resistant bacteria, free radicals, and bacterial DNA cleavage. The cytotoxicity of Ag and CuO NPs against human lung cancer cells (A-549), human colon cancer cells (HCT-8), and normal rat embryonic fibroblast cells (REF) was also investigated. The study concluded that Al-Halfaya oil field reservoirs contain a wide bacterial diversity, and the Ag and CuO NPs were effective against multidrug-resistant bacteria, free radicals, and cancer cell lines, and recommended conducting extensive studies of bacterial diversity in produced water of oil field reservoirs due to their importance in the production of many products with different applications as well as the biosynthesis of other NPs such as iron, zinc, selenium, gold, etc. by produced water bacteria. The study also recommended studying the cytotoxicity of Ag and CuO NPs on animal models and on other common cancer cell lines in addition to using these NPs for environmental applications and wastewater treatment.