The present study was aimed to investigate, the chemical composition of the essential oil extracted by hydrodistillation from Fennel (Foeniculum vulgare Mill.) harvested in South-Est, Algeria, and to evaluate its antifungal and allelopathic activities. Gas chromatography-mass spectrometry GC-MS analysis of F. vulgare essential oil showed the presence of 11 components, alpha.phellandrene (29.44%) was found as the main component. The essential oil was tested on the seeds of 2 crops (Chenopodium quinoa Willd.) Variety Q102 and (Triticum durum Desf.) variety vitron, The final germination percentages and the seedling shoot and root lengths were significantly reduced by the F. vulgare essential oil as compared to the control. Furthermore, the antifungal study on the fungi of Aspergillus niger and Aspergillus flavus reported significant results. The effectiveness of the oil showed that it has a fungicidal effect against the two strains. These findings suggest that the F. vulgare essential oil can be used as a source of environmental-friendly in bilogical control.