Nurses regularly are exposed to a variety of occupational hazards. In addition to identified occupational exposures, exposure to smoking remains a major concern. This article reviews the prevalence of smoking among nurses working in the United States and discusses their reasons for smoking. Researchers conducted a state-of-the-art review on the effects of cigarette smoking and exposure to secondhand smoke (SHS) on the immune system. Smoking prevalence among nurses working in the United States ranged from 7%-12%, and high work stress, poor work environment, shift work, and peer influence were suspected major risk factors influencing smoking behavior. A review of the effects of smoking on immunity revealed that both active smoking and exposure to SHS negatively affects immune function. When rehabilitation nurses stop smoking, their health improves and nonsmokers are exposed to less SHS. Rehabilitation nurses are encouraged to share knowledge of the immunological benefits of smoking cessation with patients to facilitate nurse-led rehabilitation programs.