The aim of this study is to investigate the effects of steaming and boiling on antioxidant and anti-inflammatory activity of five frequently consumed vegetables in winter. The vegetables were prepared by three different cooking methods including steaming, 5-minute boiling, 15-minute boiling to compare with their raw forms. Antioxidant capacity was measured with 1, 1-diphenyl–2 picrylhydrazyl (DPPH) radical scavenging method, anti-inflammatory activity was measured with 5-lipoxgenase inhibitory method, and the total phenolic content was detected after in vitro cooking process. The highest antioxidant activities among the raw vegetables were found in spinach (SR) (425.80 µg/mL, 12.83 mg/g) and broccoli (BR) (754.50 µg/mL, 7 mg/g). While boiling for 15 minutes and steaming slightly increased the antioxidant capacity in spinach and decreased it in broccoli; the highest activities among the mentioned cooking methods and vegetable samples were detected in these two vegetables. The lowest antioxidant activities were determined in leek (LR) (5662.0 µg/mL, 1.24 mg/g) and celery (CeR) (2796.0 µg/mL, 2.98 mg/g). In addition, the least affected vegetable from the cooking methods was spinach (S) (227.4-549.8 µg/mL). Cooking techniques have significative effects on the levels of phytochemical compounds and antioxidant capacities. It was observed that cooking methods increased the anti-inflammatory activity of the vegetables used in this study. Only broccoli (B) showed a decrease. The highest anti-inflammatory activity was found in the leek (L15) which was boiled for 15 minutes. Also, our results contribute to the databases that provide information about the effects of different cooking techniques on the antioxidant and anti-inflammatory potential of vegetables.