The simplest way to prevent passive exposure of children to tobacco smoke is to encourage and support their parents to quit smoking. For parents and other family members who will not or cannot quit smoking, the next best course of action is to make the home environment in which children live completely smoke-free. Primary care health professionals, in common with all health professionals, therefore need to engage with smoking prevention and cessation initiatives at all levels, but particularly in all contacts with individual patients who smoke, or family members who smoke. As educators, GPs and practice nurses can explore with GP and nursing trainees the importance of smoking cessation in preventing disease and improving health, an element that is barely covered in the traditional organ-based medical school curricula. [With external links to the evidence base]