The chemical composition of essential oil isolated from Chrysanthemum fontanesii and C. coronarium by hydrodistillation, was analysed by GC and GC/MS. A total 66 compounds representing 97.9% of the oil were identified in C. fontanesii, and 44 components representing 97.2% of the total oil in C. coronarium. The chemical composition of C. fontanesii and C. coronarium, is very different, the only common components are α-pinene, β-pinene, myrcene and Δ3-carene. The Essential oil of C. fontanesii and C. coronarium was tested for antibacterial activity against nine bacteria strains. The oil showed modest effect against Staphylococcus aureus ATCC 25923, and it has no significant antibacterial activity against the other bacteria tested. The population of C. fontanesii studied showed a diploid chromosome number 2n = 2x = 18 and a tetraploid 2n = 4x = 36 for C. coronarium.