Appearance of egg-laying workers in honey bee colonies, under queenless condition, is considered to be one of the most important problems confronting the beekeepers.  The present study aimed to prevent the appearance of the egg-laying workers by using certain essential oils. The tested oils were spearmint, eucalyptus, fennel, citronella, coriander, geranium, anise and thyme oils. Significant differences in worker ovarian development index were found between most of essential oils and control.  The lowest value of ovarian development index (the highest inhi-bitory effect) was recorded by using spearmint and fennel oils, inducing 80 and 64% ovarian inhibition as compared to control.  Whereas the highest value of ovarian index (the lowest inhibitory effect) was recorded by using thyme oil, resulting only in 24% ovarian inhibition.  However, using of anise oil gave a converse result, resulting 4% activation of ovarian development. According to results the essential oil types could be classified into four categories depending on their inhibition or activation effects on ovarian development of bee workers as follows: the first category (strong inhibition), the percentage of inhibitory effect was more than 60%, which included spearmint and fennel oils.  The second category (considerable inhi-bition), the inhibitory value ranged from 50-60%, included eucalyptus, citronella and geranium oils.  The third one (slight inhibition), the inhibitory value ranged from 0<50%, included coriander and thyme oils. While the fourth (activation), the value was less than 0%, included anise oil.  The appearance of egg-laying workers was recorded only by using thyme, anise oils and control (without oils).