A descriptive cross sectional study was conducted on a group of workers (185 medical and 215 non-medical) in the National Cancer Institute (NCI), Cairo University. Their smoking pattern, regarding knowledge, attitude and behavioral characteristics, and opinion about smoking regulations at work-place were studied. The medical workers were significantly more knowledgeable about smoking-related health hazards than the non-medical and education was significantly more informative for them. There was no significant difference between the medical and non-medical groups regarding their smoking behavior, attitude and opinion about smoking regulations at work-place. The study group was also classified into smokers and non-smokers according to their smoking status. Non-smokers were significantly more knowledgeable about smoking hazards and religion was significantly more informative for them. There was a significant difference between smokers and non-smokers regarding their opinion about smoking regulations at work-place. The study concluded that knowledge about smoking-related health hazards isn't enough to protect against smoking and it is needed to put into consideration the addictive nature of tobacco. The study recommends making National Cancer Institute a smoke-free institute, an antismoking clinic should be established at the NCI to help those trying to quit and "General Practitioners Stop-Smoking Training Courses" should be scheduled for all recently graduated physicians.