The essential oil was obtained from the aerial flowering parts of Tanacetum fisherae, a new record from Iran, by hydrodistillation and analyzed by GC and GC-MS. Eleven components representing 99.9% of the total oil were identified. 1,8-Cineole (79.9%) was characterized as the principal compound. The essential oil and its main component were tested against nine microbial strains. The result of the bioassays revealed that the oil possess potent antimicrobial property. This may be associated due to the presence of 1,8-cineole in the oil which tested individually and its high activity was observed. Micromorphological studies of hairs by scanning electron microscopy (SEM) exhibited the presence of abundant sessile capitate glandular and medifixed T-shaped eglandular trichomes on the leaves, flowers and achene, giving useful diagnostic characters for identification of this medicinal plant.