The present study evaluates the chemical composition and antimicrobial activity of essential oils (EOs) of Juniperus Phoenicea of five localities from eastern Algeria. The analysis and identification of the components of the Eos was performed using the (GC-MS). The average yield of essential oil of the samples is 0.82%. The chemical composition of the EOs of J. Phoenicea is dominated by the presence of a major product, α-pinene (36.3-55.9%). Three components are represented with large concentrations, terpinolene (0-13%), Δ3-carene (0-12.4%) and the β-phellandrene (0-7.3%). Our investigation allows us to support the species Juniperus phoenicea of eastern Algeria has several variability quantitative and qualitative. The antimicrobial activity of the essential oils of J. phoenicea was evaluated against nine bacteria. The results showed a variable degree of antibacterial activity being the population Elhadjaz most effective.