Satureja kitaibelii Wierzb. ex Heuff. has a great importance in Serbian ethnopharmacology/herbal traditional medicine, as well as a flavoring food additive. Ethanol extract of aerial parts of Satureja kitaibelii analyzed by liquid chromatography-mass spectrometry revealed the presence of 18 compounds among which the most abundant were phenolic acids, flavonoids, jasmonic acid derivatives and rosmanol. The extracts were rich in total phenolics and flavonoid contents, while rosmarinic acid was the dominant compound (18.30–29.52 mg/g). As assessments of antioxidant properties of natural extracts are important because of their growing use in medicine and food industry, antioxidant activity of ethanol extracts of Satureja kitaibelii was analyzed by several assays. The half maximal scavenging capacity (SC50) of 2,2′-diphenyl-1-picrylhydrazyl ranging from 71.20 to 125.65 μg/mL, the total antioxidant capacity from 272.37 to 714.12 mg ascorbic acid/g, and ferric ion reducing antioxidant power ranging from 0.74 to 1.94 μmol Fe/mg, clearly imply a significant antioxidant potential of Satureja kitaibelii. The extracts inhibit growth of Micrococcus luteus and Pseudomonas aeruginosa with inhibition zones 20–30 and 16–26 mm, respectively. Antioxidant and antibacterial activity of compounds identified in extracts suggest a great potential for Satureja kitaibelii application as valuable food ingredient.