Abstract: Ethanol, methanol, and hexane extracts from Ocimum basilicum Labiatae (sweet basil) were investigated for their invitro antimicrobial properties. A total of 146 microbial organisms belonging to 55 bacteria, and four fungi, and a yeast species were studied using a disk-diffusion and minimal inhibition concentration (MIC) method. The result showed that none of the three extracts tested have antifungal activities, but anticandidal and antibacterial effects. Both the hexane and methanol extracts, but not the ethanol extracts, inhibited three isolates out of 23 strains of Candida albicans studied. All three extract of O. basilicum were different in terms of their antibacterial activities. The hexane extract showed a stronger and broader spectrum of antibacterial activity, followed by the methanol and ethanol extracts, which inhibited 10, 9 and 6% of the 146 bacterial strains tested, respectively. The minimal inhibition zones (MIC) of the hexane, methanol, and ethanol extracts ranged from 125 to 250 µl/ml, 62.50 to 500 µl/ml, and 125 to 250 µl/ml, respectively. Ocimum basilicum Labiatae Ekstrakt›n›n Antimikrobiyal Etkisi Ozet: Ocimum basilicum Labiatae (sweet basil)'un etanol, metanol ve hegzan ekstraktlar›n›n antimikrobiyal ozellii invitro koflullarda araflt›r›ld›. 55 bakteri, 4 fungus ve bir mayadan oluflan toplam 146 mikroorganizma, disk difuzyon ve minimal inhibisyon konsantrasyonu (MIC) yontemleri kullan›larak cal›fl›ld›. Sonuclar, test edilen 3 ekstrakttan hicbirinin antifungal aktivite gostermediini fakat antikandidal ve antibakteriyal etkiye sahip olduunu ortaya koydu. Hem hegzan hem de metanol ekstraktlar› 23 Candida albicans turunden 3 tanesine karfl› inhibisyon etkisi gosterirken, etanol ekstrakt› gostermedi. O. basilicum'un 3 ekstrakt› da farkl› oranlarda antibakteriyal etki gosterdi. Hegzan ekstrakt›, metanol ve etanole ekstraktlar›na gore daha guclu ve genifl oranda antimikrobial etkiye sahip olup, test edilen 146 bakteri strainine karfl› s›ras›yla %10, 9, 6 oranlar›nda inhibisyon etkisi gosterdi. Hegzan, metanol ve etanol ekstraktlar›n›n minimal inhibisyon konsantrasyon (MIC) oranlar› s›ras›yla, 125-250 µl/ml, 62.50-500 µl/ml ve 125-250 µl/ml'dir