Essential oils (EO) from fresh and dry aerial parts of Pituranthos chloranthus (Benth.) Hook and Pituranthos tortuosus (Coss.) Maire were isolated by hydrodistillation and analyzed by GC/MS. The main constituents of the EO obtained from fresh herb of P. chloranthus were found to be α-pinene, sabinene, cis-ocimene and myrcene. In dry biomass, a significant increase of the content of some compounds such as α-phellandrene, △,3-carene and β-phellandrene characterized the oil. Minor changes in the chemical composition of the P. tortuosus EOs obtained from fresh or dry herbs and the major constituents were found to be sabinene and myrcene with equilibrate amounts of α-pinene, p-cymene, cis-ocimene, limonene, trans-β-ocimene, γ-terpinene and cis-verbenol. The paper disc diffusion method was used to evaluate the antibacterial activity and results showed an important inhibitory effect of oils obtained from fresh herb against most tested bacteria.