The chemical compositions of the essential oils obtained from the aerial parts of Helichrysum rupestre and H. ambiguum were analysed by GC and GC/MS. From the forty-five identified constituents representing 90.21% and 93.90% of the two oils, respectively, manoyl oxide, dodecanal, nonanal, p-cymene, alpha-pinene, and 2,4,6-tris(1,1-dimethylethyl)benzoic acid, were found to be the major components. Furthermore, the oils were tested against six Gram (+/-) bacteria and it was found that one of them exhibited significant antibacterial activity.