Essential oils from Ocimum basilicum L. and Coriandrum sativum L. varieties originating from Turkey were investigated for their antimicrobial properties. The antimicrobial effects of the oil varieties were evaluated by the disc diffusion and minimum inhibitory concentration (MIC) methods against eight bacteria and three fungi. The compositions of the essential oils were analyzed and identified by GC and GC-MS. O. basilicum, C. sativum var. macrocarpum and var. microcarpum oils revealed the presence of linalool (54.4%), eugenol (9.6%), methyl eugenol (7.6%); linalool (78.8%), gamma-terpinene (6.0%), nerol acetate (3.5%); and linalool (90.6%), and nerol acetate (3.3%) as the major components, respectively. The oils exhibited antibacterial activity ranging from 1.25 to 10 microL disc(-1) against the test organisms with inhibition zones of 9.5-39.0 mm and minimal inhibitory concentrations values in the range 0.5- > or =1 microL/L. Linalool, eugenol, and methyl eugenol at 1.25 microL disc(-1) had antimicrobial effects on all microorganisms, giving inhibition zones ranging from 7 to 19 mm.