Variation on yield and composition of the essential oil of Syzygium aromaticum buds from Madagascar at different phenological stages including young bud stage, budding stage 1, budding stage 2, budding stage 3, full budding stage, flowering stage, initial fruiting stage, full fruiting stage are reported. The essential oil yield varied from 2.52% to 17.94%, reaching a maximum at the end of budding stage, after which it rapidly decreased. The essential oil was analyzed by GC and four constituents were identified and quantified for whole phenological stages. Eugenol and eugenyl acetate were the main compounds in all samples. Eugenol, was lower in the young bud stage (39.66%) and increased in the subsequent phenological stages to reach maximum in the full fruiting stage (94.89%). In contrast, eugenyl acetate was higher in the young bud stage (56.07%), after which decreased to reach minimum in the full fruiting stage (2.01%).