Abstract: Three formulations of copper salts or copper complexes encapsulated by different kinds of polymers were locally prepared in the Polymers and Pigments Department. The biological activity of these compounds were studied against various types of fungal strains. The dose and the rate of leaching of copper ions were also studied. They were significantly controlled by the type of the polymer film used and the solubility in the medium. The effective doses of the biocide were (0.1- 0.2 mg/ml). The different kinds of used polymers improved the tenacity of the fungicides on the leaf surfaces and improved the dispersion of copper salt suspension. The results provided laboratory support for the concept that the polymers containing chemically bound biocides were useful for controlling microorganisms growth. In field application, the role of polymer film is obviously clear in the protection of most copper salts or complexes that can be used in rainy and windy places to obtain both economic and environmental advantages. The copper uptake by fungal strains were studied to determine their difference in behavior to the biocidal activity of these compounds. The uptake strategy was examined by Transmission Electron Microscope (TEM). In addition, the cytological studies on and in cucumber leaves showed an efficient intracellular diffusion of copper ions. The acute toxicity of these compounds was also studied.