Five essential oils: peppermint (Mentha piperita), spearmint (Mentha viridis), marjoram (Marjorana hortensis), lavender (Lavandula officinalis) and sweet basil (Ocimum basilicum) were tested against embryonated eggs, unfed larvae and fed females of the cattle tick Boophilus annulatus. L. officinalis was more toxic on embryonated eggs (LC50: 0.36%) followed by M. piperita (LC50: 0.39%), O. basilicum (LC50: 0.52%), M. hortensis (LC50: 1.06%) and M. viridis (LC50: 1.20%). Toxicity of oils on unfed larvae decreased gradually from O. basilicum (LC50: 0.05%) to L. officinalis (LC50: 0.69%), M. hortensis (LC50: 0.75%), M. piperita (LC50: 0.77%) and M. viridis (LC50: 0.90%). LC50 of M. hortensis on fed females was 0.52% followed by O. basilicum, M. piperita, L. officinalis and M. viridis that were 1.01, 2.85, 3.25 and 10.57%, respectively. In conclusion these oils had toxic effects on all experimental stages of B. annulatus except of M. viridis was less toxic on fed females.