The objective of the research study was to determine the basic chemical composition and the content of bioactive components in some selected cultivars of garlic (Allium L.). The experimental material consisted of winter cultivars: ‘Ornak’, ‘Mega’, ‘Harnaś’ and ‘Arkus’, garlic from China and Spain, organic garlic as well as ‘Jankiel’ spring cultivar. In the fresh material, there were determined the contents of dry weight and vitamin C. In the lyophilized samples, there were assayed the contents of minerals in the form of ash, protein, fat, and dietary fibre. The content of total polyphenols and the free radical neutralizing capability (using a free ABTS^•+ radical) were determined in the methanol extracts prepared from fresh garlic. Statistically significant (p ≤ 0.05) differences were reported to exist among the contents of the components analysed (except for the content of fat) and they were dependent on the garlic cultivar. The garlic from Spain constituted the best source of mineral compounds in the form of ash. The Polish winter cultivars: ‘Mega’ and ‘Ornak’ were characterized by a high content of protein. The ‘Harnaś’ cultivar and the garlic from Spain were reported to have the highest amount of total carbohydrates. The highest content of dietary fibre was determined in the ‘Harnaś’ garlic cultivar. The ‘Jankiel’ spring cultivar contained the highest amount of vitamin C whereas the garlic from China the highest amount of total polyphenols. No correlation was reported to exist between the content of bioactive components assayed and the antioxidant activity.