In the present study, the effect of boiling, stir-frying, steaming, oven-baking, and microwaving on vitamins content, proximate composition, minerals content and their bioaccessibility, pigments level, phenolic compounds (rutin, rosmarinic acid, and quercetin), and antioxidant activity of basil (Ocimum basilicum L.) leaves were evaluated. Cooking was reduced the mineral content and the lowest bioaccessibility were interestingly found for heavy minerals. Boiling caused a significant decrease in water-soluble vitamins and minerals content, whereas, stir-frying caused losses the fibre, protein, and carbohydrate content more than the other cooking methods. Furthermore, steaming and microwave methods were able to retain most of the protein, water-soluble vitamins, minerals, phenolic compounds, and antioxidant activity and may thus be selected as suitable methods for cooking basil based foods and recipes.