Bladder cancer considered as the ninth most common cancer worldwide. Studies suggested that bladder cancer influenced by environmental factors, such as cigarette smoking and chemicals. Smoking is well established as one of the strongest risk factors of bladder carcinoma. It is reported that awareness about smoking and bladder cancer risk is poor. This cross–sectional study conducted to assess level of awareness of the risk of smoking on bladder cancer in Alhasa population. 373 participants were selected randomly. Data analyzed by SPSS version 23. Only (20%) of smokers aware about the effects of smoking on bladder cancer. While, (37.5%) have a low level of awareness. To conclude, the knowledge of awareness in Al–Ahsa population is low. There is a need for health education to prevent complications