This work focuses on the study of the antifungal and insecticidal activities of three essential oils of wormwood (Artemisia absinthium), wild mint (Mentha arvensis) and eucalyptus (Eucalyptus officinalis) and the identification of chemical compounds that may be present in them. The use of these oils has revealed a significant fungicidal potential towards different fungal species such as Aspergillus niger, Aspergillus flavus, Sclerotium rolfsii, Sclerotium sclerotiorum, Penicillium digitatum, Fusarium solani and Fusarium oxysporum but to different degrees. Similarly, an insecticidal effect was detected for all three oils against the stored food pest Tribolium castaneum. These activities are attributed to certain chemical compounds that were identified by gas chromatography-mass spectrometry.