The importance to push scientifically the investigations on the organic extracts of the plants aromatic as potential source of new antimicrobial compounds comes from the traditional use of the plants. However, the consumption of these natural products requires à thorough research in this field. The antimicrobial effect of organic and aqueous leaves extracts of Foeniculum vulgare Mill., However, which makes difficult this antimicrobial activity, is the insolubility of organic extracts in water. The standard M27-T technique is basically used to cure this problem. The microorganisms under examination were Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus hirea, Escherichia coli and Candida albicans. The M27-T technique allowed us to determine the Minimum Inhibitory Concentrations (MICs) of different extracts. Therefore, the test's results showed that the all samples were clearly different in terms of antimicrobial activities. All extracts of Foeniculum vulgare showed the most activity on all the microorganisms tested. The most significant and active extract under study were methanol and ethyl acetate on all the bacteria tested in comparaison to the hexane and aqueous extracts. On the other hand, the results of antimicrobial activity of aqueous extract were more compelling than the hexane and dichloromethane extracts when used on Candida albicans (ATCC and CBS) (MIC = 0,78 mg mL −1 ). It then appear that C. albicans ATCC is the least susceptible microorganisms to the ethyl acetate extract. The chloramphenicol, amoxicillin and amphotericin B were used as standard antibiotics to carry this study.