The composition of the essential oil isolated by hydrodistillation from Omphalodes cappadocica (Willd.) DC. (Boraginaceae) collected from 'Of', a town in Trabzon, was determined by GC-FID and GC-MS. Sixty components were identified corresponding 90.8 % of the oil. The major components were benzaldehyde (18.1 %), nonanal (10.0 %), 2E-nonenal (8.1 %), tricosane (4.4 %), octanal (3.9 %), 2-pentyl furan (3.8 %), 2E,6Z-nonadienal (3.7 %) and 2E,4E-decadienal (2.7 %). In addition, antimicrobial activity of the essential oil of O. cappadocica was investigated against Escherichia coli, Yersinia pseudotuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Mycobacterium smegmatis and Candida albicans and Saccharomyces cerevisiae at maximum essential oil concentration in hexane of 1000 mu g/mL. They showed only antibacterial activity against bacteria E. coli, S. aureus, B. cereus, M. smegmatis and the fungicidal activity against C. albicans and S. cerevisiae.