This paper briefly reviews the health hazards associated with smoking, including passive smoking, with specific reference to local (Hong Kong) evidence. A Medline search of Hong Kong papers from January 1966 to January 1998 was made, and these and other relevant papers were reviewed. In Hong Kong, at least 10 people die daily from smoking- related diseases. Local studies show that smoking is associated with lung cancer, oesophageal cancer, liver cancer, ischaemic heart disease, peripheral vascular disease, ischaemic stroke, peptic ulcer, osteoporosis, impaired lung function, respiratory symptoms, and other adverse health effects. Smoking in pregnant women can result in smaller babies being born. Pooled results from four case-control studies show a 60% excess risk of lung cancer due to exposure to environmental tobacco smoke. Several studies confirm the link between exposure to environmental tobacco smoke and respiratory illness, hospitalisation, and asthma in children. The risks of smoking (one of every two smokers will be killed by tobacco) are not well known and are underestimated by both doctors and the public. Stronger health messages and more local evidence are needed to support tobacco control in Hong Kong.