An experiment was conducted to study the effects of solar UV radiation, UV-B, UV-C radiation, and elevating CO₂ on some physiological attributes of two canola cultivars (Brassica napus L.) under complete irrigation or limited irrigation in two continuous years. Generally, elevated CO₂ increased leaf-soluble carbohydrates, reducing sugars, glucosinolate, and Fv/Fm ratio while carotenoids and soluble protein were decreased due to elevated CO₂. In addition, UV radiation decreased leaf-soluble carbohydrates, reducing sugars, chlorophyll, proline, and Fv/Fm ratio and increased UV absorbing pigments, soluble proteins, and glucosinolate.